glowa volta - zef...glowa volta phase iii completion report report period: 01.06.2006 – 31.05.2009...
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GLOWA Volta
Phase III completion report Report period: 01.06.2006 – 31.05.2009
(Submitted in January 2010) Förderkennzeichen 01/LW 0302 B
Jens Liebe, Claudia Arntz and Paul L.G. Vlek (Eds.)
submitted to
Bundesministerium für Bildung und Forschung
by the
Center for Development Research,
Rheinische Friedrich-Wilhelms-Universität Bonn
2
Outline
Abbreviations ................................................................................................................................... 4
List of Figures ................................................................................................................................ 11
List of Tables .................................................................................................................................. 15
1. Introduction: The third project phase of GLOWA Volta: Synthesis and Transfer .................... 16
1.1 Objectives and Structural setup of research clusters ....................................................... 17
1.2 Capacity Building ............................................................................................................ 21
1.3 Project Presentation and Media Coverage ....................................................................... 24
2. Achievements and research results of the sub-projects .............................................................. 26
2.1. Completed work from Phase II Clusters and ongoing projects which contribute to several
clusters ........................................................................................................................................ 26
2.2 Cluster S Water Supply and Distribution ............................................................................. 50
2.2.1 Sub-project S1: Hydrometeorological Modeling (MM5 and WaSiM) ......................... 50
2.2.2 Sub-project S2: Hydro-meterological Observatory ....................................................... 67
2.2.3 Sub-project S3: Remote Sensing and Surface Energy Flux .......................................... 74
2.2.4 Sub-project S4: Surface, Soil and Groundwater ........................................................... 86
2.3 Cluster E Analysis of Long-Term Environmental Change .................................................... 100
2.3.1 Sub-project E1: Automated Classification of Remotely Sensed Imagery .................. 100
2.3.2 Sub-project E2: The Basin Wide Cellular Automata LUCC Model ........................... 107
2.3.3 Sub-project E3: GV LUDAS. A High Resolution Agent-Based Model ..................... 109
2.3.4 Sub-project E4: Land-use Change Predictions and impact on Land- and water-use
Policies ................................................................................................................................. 112
2.4 Cluster D Water Demand ................................................................................................... 122
2.4.1 Sub-project D1: Agricultural Water Demand ............................................................. 122
2.4.2 Sub-project D2: Non-Agricultural Water Demand ..................................................... 126
2.4.3 Sub-project D3: Integrated Demand Simulation Framework ..................................... 131
2.5 Cluster C: Participatory Decision Support and Coordination of Technology Transfer ..... 135
2.5.1 Sub-project C1: Participatory Decision Support and Coordination of Technology
Transfer ................................................................................................................................ 135
2.5.2 Sub-project C2: Transboundary Water Management.................................................. 138
2.5.3 Sub-project C3: Consortium Building, training and outreach in the use of DSS ....... 143
2.6 Cluster I: GLOWA Volta Decision Support System ......................................................... 148
2.6.1 Sub-project I1: Requirements Engineering ................................................................. 148
2.6.2 Sub-project I2: GVDSS Infrastructure ........................................................................ 161
3
2.6.3 Sub-project I3: GVDSS Workbench ........................................................................... 170
3. Summary and Conclusion ........................................................................................................ 177
4. Publications .............................................................................................................................. 180
4.1 Completed Theses .............................................................................................................. 180
4.2 Journal Articles .................................................................................................................. 182
4.3 Books .................................................................................................................................. 194
4.4 Book Sections ..................................................................................................................... 195
4.5 Conference Paper ............................................................................................................... 197
4.6 Conference Proceedings – Presentations and Posters ........................................................ 203
4.7 Documentation of research ................................................................................................. 214
4
Abbreviations
AARSE African Association of Remote Sensing
of the Environment
AEJ African Easterly Jet
AMMA African Monsoon Multidisciplinary
Analysis
ANN Artificial Neural Network
APSIM Agricultural Production Systems
Simulator
ATCOR Atmospheric & Topographic Correction
AVN Aviation Model
BF Burkina Faso
BIGS-DR Bonn International Graduate School for
Development Research
BIOTA Biodiversity Monitoring Transect Analysis
BMBF Federal Ministry of Education and
Research – Germany
BNP Bontioli National Park
BON Biophysical Observation Network
B2B Business-to-business
CA Cellular Automata
CEC Cation Exchange Capacity
CGIAR Consultative Group on International
Agricultural Research
CIDA Canadian International Development
Agency
CIRAD Centre de Coopération Internationale en
Recherche Agronomique pour le
Développement
COBIDS Component-Based Integration of Data
and Services
CP Circulation Pattern
CPU Central Processing Unit
CPWF Challenge Program for Water and Food
5
CR Clay Ratio
CRFS Centre de Recherches et de Formation
Scientifique
CRSN Centre de Recherche en Santé de
Nouna
CsDM Diffusion and Migration Calibration Model
CSF GVP Common Sampling Frame
CSIR Council for Scientific and Industrial
Research
CsMB1 Mass Balance 1 Calibration Model
CsMB2 Mass Balance 2 Calibration Model
CsPM Proportional Calibration Model
CWSA Community Water and Sanitation Agency
DA District Assembly
DAAC NASA Distributed Active Archive Center
DANIDA
Danish International Development
Agency
DBH Diameter at Breast-Height
DBM Data-based mechanistic
DEM Digital Elevation Map
DGIRH Direction Générale de l'Investissement
dans les Ressources Humaines
DLR German Aerospace Center
DMSP Defense Meteorological Satellite
Program
DOY Day of Year
DSS Decision Support System
ECHAM4 Atmospheric General Circulation Model
ECMWF European Center for Medium Range
Weather Forecasting
ECOWAS
Economic Community of West African
States
EDI Effective Drought Index
EM Expectation Maximization
EPA Environmental Protection Agency -
Ghana
ESA European Space Agency
6
ET Evapotranspiration
etr Evapotranspiration (in WaSiM)
ETref Reference Evapotranspiration
FAO Food and Agriculture Organization
GAMS General Algebraic Modeling System
GCM General Circulation Model
GDP Gross Domestic Product
GEF Global Environment Facility
GHG Greenhouse gases
GIRE Gestion Intégrée des Ressources en Eau
GIS Geographic Information System
GLOWA Global Change in the Hydrological Cycle
GMP Governance and Modeling Project
GPS Global Positioning System
GUI Graphic User Interface
GV LUDAS GLOWA Volta Land Use Dynamics
Simulator
GVP GLOWA Volta Project
GWCL Ghana Water Company Limited
GWP Global Water Partnership
GWP-WAWP Global Water Partnership West Africa
HMMS Hydro-Meteorological Monitoring System
HSD Hydrological Services Division - Ghana
ICOUR Irrigation Committee of Upper East
Region
IFPRI International Food Policy Research
Institute
IGBP
International Geosphere-Biosphere
Program
IRD Institut de Recherche pour le
Développement
IMF International Monetary Fund
IMK-IFU Institute of Meteorology and Climate
Research - Atmospheric Environmental
Research Division
INERA Institut de l‟Environnement et de
Recherche Agricoles
7
ITD Inter-Tropical Discontinuity
IUCN World Conservation Union
IWMI International Water Management
Institute
IWRM Integrated Water Resources
Management
KACE Kofi Annan Center of Excellence in
Information and Communications
Technology
LAI Leaf Area Index
LANDSAT ETM LANDSAT Enhanced Thematic Mapper
LANDSAT TM LANDSAT Thematic Mapper
LAS Large-Aperture Scintillometry
LC Land Cover
LCCS Land Cover Classification System
LPJ-model Lund – Potsdam - Jena Dynamic Global
Vegetation Model
LSA-SAF Land Surface Analysis Satellite
Application Facility
LST Land Surface Temperature
LUC Land Use / Cover
LUCC Land use and land cover change
LUDAS Land Use Dynamics Simulator
LULC Land Use and Land Cover
MAS Multi-Agent System
MATA Multi-Level Analysis Tool for Agriculture
METOP Meteorological Operational Satellite
MM5 Mesoscale Meteorology Model 5
MODIS Moderate Resolution Imaging
Spectroradiometer
MoFA Ministry of Food and Agriculture - Ghana
MoWH Ministry of Works and Housing -Ghana
MSG Meteosat Second Generation
NAO North Atlantic Oscillation
NARMAX Nonlinear Autoregressive-moving
Averages Model with Exogenous Input
8
NASA National Aeronautics and Space
Administration
NCEP National Center for Environmental
Prediction
NCWSP National Community Water and
Sanitation Program - Ghana
NDVI Normalized Difference Vegetation Index
NGO Non-Governmental Organization
NOAA-AVHRR National Oceanic & Atmospheric
Administration - Advanced Very High
Resolution Radiometer
NPP Net Primary Production
NRB Nature Reserve of Bontioli
NUSLE Nomograph Universal Soil Loss Equation
OGSA-DAI Open Grid Services Architecture Data
Access and Integration
OPUS Open Platform for Urban Simulation
ORS Onset of the Rainy Season
PAGEV Projet pour l‟Amélioration de la
Gouvernance de l‟Eau dans le Bassin de
la Volta
PbDM Diffusion and Migration Model for 210Pb
PbMB Mass Balance Model for 210Pb
PERL Practical Extraction and Report
Language
PEST Parameter Estimation Tool
PPP Public Private Partnership
prec Precipitation
PSF Particle Size Fractions
PSP Private Sector Participation
PTF Pedo-Transfer Function
PURC Public Utilities Regulatory Commission –
Ghana
qdir Direct runoff (in WaSiM)
qifl Interflow (in WaSiM)
qtot Total runoff (in WaSiM)
RCM Regional Climate Model
9
REDD Reducing Emissions from Deforestation
and Degradation
RMSE Root Mean Square Error
RN Net Radiation
RS Remote Sensing
SARI Savannah Agricultural Research Institute
SAWSDL Semantic Annotations for Web Service
Definition Language
SEBAL Surface Energy Balance Algorithm for
Land
SGI Shallow groundwater irrigation
SMOS Soil Moisture and Ocean Salinity
SOFM Second-Order-First-Moment
SPOT Satellites Pour l‟Observation de la Terre
SR Sand ratio
SRP Small Reservoirs Project
SRTM Shuttle Radar Topography Mission
SSWE small-scale water entrepreneurs
SVAT Surface-Vegetation-Atmosphere-
Transfer
SVN Social Venture Network
SVRT SMOS Validation and Retrieval Team
SWAT Soil & Water Assessment Tool
TEJ Tropical Easterly Jet
TU Technical University
UER Upper East Region - Ghana
UML Unified Modeling Language
UN United Nations
UNU United Nations University
USP Unit Stream Power
USAID Unites States Agency for International
Development
USDS-ARS United States Department of Agriculture
– Agricultural Research Service
USGS United States Geological Survey
USLE Universal Soil Loss Equation
UTM Universal Transverse Mercator
10
VBA Volta Basin Authority - Ghana
VBTC Volta Basin Technical Committee
VF Vegetation Fraction
VRA Volta River Authority -Ghana
WAPP West African Power Pool
WaSiM-ETH Water Balance Simulation Model
WaTEM/ SEDEM Water and Tillage Erosion Model /
Sediment Delivery Model
WATSAN Water and Sanitation Committee -
Ghana
WEPP Water Erosion Prediction Project
WFMS Work Flow Management Systems
WRC Water Resources Commission - Ghana
WRI Water Research Institute
WUA Water User Association - Ghana
WVPP White Volta Policy Pilot Project
ZEF Center for Development Research
11
List of Figures
Figure 1: GLOWA Volta Phase III Research Clusters .................................................................. 18
Figure 2: The GLOWA Volta Decision Support Resources .......................................................... 20
Figure 3: GLOWA Volta Students ................................................................................................. 21
Figure 4: The GLOWA Volta Research Network .......................................................................... 23
Figure 5: Digital elevation model of a small reservoir in southwestern Burkina Faso based on
bathymetric measurements ..................................................................................................... 28
Figure 6: Spatial pattern of soil erosion and deposition at a hill slope in south-western Burkina
Faso based on a 137
Cs conversion model ................................................................................ 30
Figure 7: Urban and Rural Growth in Africa ................................................................................. 32
Figure 8: Urban and Rural Growth in Ghana ................................................................................. 33
Figure 9: Sprawl of Accra, Ghana from 1985 until 2000 ............................................................... 34
Figure 10: Software Package Relationships ................................................................................... 36
Figure 11: Annual Cycle of a Simulation Run ............................................................................... 37
Figure 12: Round in Jamestown, Korle-Bu District illustrating Plot Land Value and Land Use
(Green – Residential; Blue – Commercial; Brown – Institutional; Government – Not Shown
Here) ....................................................................................................................................... 38
Figure 13: Plots of the Korle Bu District ....................................................................................... 40
Figure 14: Erosion control program at a village in the Volta Basin .............................................. 46
Figure 15: Screenshot LAMPT ...................................................................................................... 48
Figure 16: WaSiM setup: derived river network and boundaries of the White Volta Basin and its
subcatchments ........................................................................................................................ 52
Figure 17: Coupling strategy for using atmospheric information in hydrological modeling ......... 53
Figure 18: Measured (Hydro Argos) water level [m] at Yarugu/Kaburi from 2004 until 2007 .... 54
Figure 19: Spatial distribution of simulated annual precipitation (MM5 Domain 3) for the Volta
Basin for 2004 [mm] .............................................................................................................. 55
Figure 20: of monthly averaged simulated vs. observed precipitation (MM5 simulation results are
shown for domain 2 and domain 3 - real time and scaled) .................................................... 55
Figure 21: Routed vs. measured (black) discharge [m3/s] for Nawuni for 2004 using (a) gridded,
real time (MM5 D2 and MM5 D3) or scaled (MM5 D2 sc and MM5 D3 sc) MM5 results,
and (b) gridded, scaled TRMM product 3B42 or station data ............................................... 56
Figure 22: Seasonal cycle of monthly mean precipitation [mm/month], leaf area index LAI (red)
and surface albedo (green) averaged over the White Volta Basin for 2004 .......................... 57
12
Figure 23: Annual potential evapotranspiration [mm] for the White Volta Basin for 2004 using
(a) static tabulated values for albedo and LAI, and (b) dynamic MODIS estimates for albedo
and LAI .................................................................................................................................. 58
Figure 24: Results of hydrological simulations using “Turning Bands” simulated precipitation
fields for 2004: (a) Spatial distribution of standard deviation of total discharge [mm], and (b)
time series of daily range (grey) and mean value (black) for precipitation (top), and routed
vs. measured (red) discharge (bottom) for Nawuni ................................................................ 60
Figure 25: Observed (*) and fitted (-) dry spell occurrence probability within the following 30
days for each day of the year at Bole, based on rainfall data from 1961 to 1999 .................. 62
Figure 26: Date with minimum dry spell occurrence probability for the following 30 days,
representing the optimal planting date [Day of Year]. External drift kriging, including
distance-to-sea information, was applied for spatial interpolation ........................................ 63
Figure 27: Probability of the dry spell occurrence within the following 30 days [%]. External drift
kriging, including distance-to-sea information, was applied for spatial interpolation ........... 64
Figure 28: Location of the Volta Basin and spatial distribution of areas with similar rainfall
characteristics, represented by five ellipses (right), (source: Laux et al., 2007). ................... 65
Figure 29: Isolines of bivariate drought duration and drought intensity return periods TDS for the
- case in region A (top) and region E (bottom) using 10-day moving-averaged EDI values.
The dots represent the single drought events. The location of the regions within the Volta
Basin is shown in Laux et al. (2009) ...................................................................................... 66
Figure 30: Precipitation anomaly (top) and difference between simulated mean crop yield (MCY)
using the ORS definition and simulated MCY using the traditional planting date (15 May,
DOY 135) for maize and groundnut (bottom) at Garoua (Cameroon) .................................. 67
Figure 31: Map of the Volta Basin with the principal rivers. The dotted lines represent the study
area covering a large part of the White Volta Basin; the black lines correspond to the Land
Use/Land Cover (LULC) map around Navrongo. ................................................................. 76
Figure 32: Maps of ET, sensible heat flux, and soil moisture (degree of saturation) at the end of
the rainy season (October 30, 2002) derived from Landsat image. The scale of these maps is
different from Figure 33 since these maps cover two Landsat images. The area of Figure 33
is the lower half of this figure. ............................................................................................... 77
Figure 33: Maps of ET, sensible heat flux, and soil moisture (degree of saturation) at the end of
the dry season (March 7, 2003) derived from Landsat image (Path 194, Row 53). The scale
of these maps is different from Figure 32 since these maps cover the lower half of Figure 32.
There is some contamination by clouds in the upper NW corner of the image. .................... 78
Figure 34: MODIS and Landsat images at the end of the rainy season. The Landsat image is
composed of two images (Path 194, Rows 52 and 53). At the end of the dry season (March
7, 2003) only the southern image was used (Path 194, Row 53). .......................................... 79
13
Figure 35: Evaporation histograms of Landsat and MODIS evaporation maps on March 7, 2003.
................................................................................................................................................ 80
Figure 36: MODIS and Landsat maps of evaporation at the end of the dry season (March 7, 2003)
in a 22 by 21 km area around Tono dam. Highest evaporation rate (>7 mm/day) is black,
zero evaporation is white. ....................................................................................................... 80
Figure 37: Landsat and MODIS images covering the Middle Rio Grande Valley in New Mexico,
USA. The Landsat and MODIS images have different temporal and spatial resolutions. ..... 81
Figure 38: ET maps from output up-scaling using simple averaging resampling on June 16, 2002.
Spatial resolutions are 60, 120, 250, 500 and 1000 m from the left. This method produces
the most statistically and spatially predictable behavior (Hong et al., 2009a). ...................... 83
Figure 39: Down-scaled ET map from four different down-scaling procedures (1) output with
subtraction, (2) output with regression, (3) input with subtraction and (4) input with
regression. Output with regression is the preferred procedure. Enlarged areas (6 x 9 km2)
shown at the bottom correspond to the dotted square of the upper images (Hong et al.,
2009b). .................................................................................................................................... 83
Figure 40: Scatter plots of sensible heat flux measurements from serial number 030005 (x-axis)
vs the other LASs (only the last two digits of the serial number are shown in the axis labels)
for experiment H1. The grey dashed line is the 1:1 line. ....................................................... 85
Figure 41: The scintillometer transect in Boudtenga in August 2008. ........................................... 85
Figure 42: Average satellite backscatter distribution for West Africa from 1991-2000 ................ 88
Figure 43: Diurnal backscatter differences for West Africa (differences in backscatter from 10:30
am and 10:30 pm) ................................................................................................................... 89
Figure 44: Hydrotope map at the Ejura study site .......................................................................... 90
Figure 45: Hydrotope unit separated vs. regular soil moisture distribution. PDFs of a sample soil
moisture distribution divided into hydrotope units (grey lines), as well as an overall soil
moisture distribution (black line) are shown. ......................................................................... 91
Figure 46: Schematic view of elastic stem measurements ............................................................. 92
Figure 47: Physical approach. Diurnal plant water fluxes as influences by declining soil water.
On the left water movement along a tension gradient from soil to tree into the atmosphere is
shown. On the right, the diurnal flux schemes depict soil water tension (ψsoil) and resulting
plant water tension (ψplant) ...................................................................................................... 93
Figure 48: Conceptual approach. Combined tree and grass drought periods as determined by
different drought definitions for trees and grasses ................................................................. 94
Figure 49: Diurnal tree water flux in [g] during a period of declining soil water content. Green
and red dots show tree water storage at morning (green) satellite overpass times and at
evening (red) satellite overpass times .................................................................................... 94
14
Figure 50: Monthly averaged diurnal ERS backscatter differences (1992-2007) and monthly
vegetation drought period maps (2006) ................................................................................. 95
Figure 51: Map of the Volta River Basin showing the various spatial scales at which research
activities took place; the Upper East Region (area marked red), the White Volta Basin of
Ghana (area marked yellow) and the entire White Volta River Basin (area marked in dark
green) ...................................................................................................................................... 96
Figure 52: SWAT-simulated mean annual shallow groundwater recharge in the White Volta
River Basin (1980-1999) ........................................................................................................ 97
Figure 53: SWAT-simulated mean annual rainfall in the White Volta River Basin (1980-1999) . 98
Figure 54: Texture of soils in the White Volta River Basin (Schuol et al., 2008, modified after
FAO, 1995) ............................................................................................................................. 99
Figure 55: LCCS Land Cover for the GLOWA Volta Basin (1989-1991). The land cover was
derived from Landsat ETM+, MODIS, DMSP and SRTM imagery ................................... 105
Figure 56: LCCS Land Cover for the GLOWA Volta Basin (2000-2001). The land cover was
derived from Landsat ETM+, MODIS, DMSP and SRTM ................................................. 106
Figure 57: Land Cover change processes from 1990 to 2000 mapped from satellite imagery for a
region (approx. 50 by 40 kilometers) in central Burkina Faso (West Africa). The land cover
processes are illustrates by colors. Blue for instance represents land cover transformation
that is changes from natural vegetation to cropland areas (over the observation period 1990-
2000) ..................................................................................................................................... 107
Figure 58: Main conversion processes as annual changes (% of all processes, 1990-2000, Burkina
Faso sample area), mapped using remote sensing observations. The relative significances of
investigated drivers for each of the mapped land cover change processes are s shown as
fractions in the pie diagrams. ............................................................................................... 109
Figure 59: The conceptual framework of LUDAS for the coupled human-environment system 110
Figure 60: Graphic User Interface (GUI) of the GV-LUDAS model for the Atankwidi catchment
in the Upper East of Ghana .................................................................................................. 115
Figure 61: Map of the study area ................................................................................................. 142
Figure 62: Communication gaps in transboundary flood management ....................................... 143
Figure 63: Architecture for WFMS in the GLOWA Volta Project .............................................. 156
Figure 64: Example of Workflow Partitioning ............................................................................ 158
Figure 65: Workflow Execution Sequence Diagram ................................................................... 161
Figure 66: Architecture of the GLOWA Volta Geoportal ........................................................... 164
Figure 67: Votes by 19 members of institutions from the Ghanaian water sector concerning
problems with information about data ................................................................................. 165
Figure 68: Votes by 13 members of institutions from the Burkinabe water sector concerning
problems with data transfer .................................................................................................. 165
15
Figure 69: The data management workflow ................................................................................ 167
Figure 70: The GVP-Geoportal Offline Tool for editing metadata in the field without connection
to the internet. Image shows the interface to generate the Uniform Resource Name (URN)
for a metadata set .................................................................................................................. 168
Figure 71: Page of the GVP-Geoportal displaying links to interactive project maps .................. 170
Figure 72: Example visualization of poverty statistics for districts in Ghana constructed from
transformation modules using the Analytical Visualization Framework. Colored map, table
view and value distribution histogram provide different perspectives on the same data ..... 175
Figure 73: The main workspace of the Analytical Visualization Framework: Digital elevation
model of the Volta Basin at 1km x 1 km resolution. Visualization is constructed by the
design shown on Figure 72. It consists of a map display and a slider for interactive changes
in color scale ......................................................................................................................... 176
List of Tables
Table 1: Distribution of evaporation and crop coefficient (Kc) by LULC class at start (30
October, 2002) and end (March 7, 2003) of the dry season, in the Navrongo area, Ghana. .. 78
Table 2: Main Sources of Income of Households in selected communities along the White Volta
.............................................................................................................................................. 140
16
1. Introduction: The third project phase of GLOWA Volta: Synthesis and Transfer
The GLOWA Volta Project
The Volta River Basin in West Africa is in many aspects representative of large basins in
the developing world. With regard to water resources management it is among the most
challenging and most interesting basins to study in Africa. It shows steep gradients in
precipitation, spans over four agro-ecological zones, and is shared by six riparian
countries, of which the two largest, Burkina Faso and Ghana, are situated in a distinct
upstream/downstream constellation. GVP focuses its research on these two main
riparian countries, Burkina Faso and Ghana, which occupy the great majority of the
400,000km² of the Volta Basin, of 42% and 40% respectively.
The challenges the basin faces are manifold, such as the effects of global environmental
change on the spatial and temporal distribution of water and its quantities, increasing
demand through steep population growth, agricultural and industrial development, and
growing demand for hydropower. A peculiar situation in the Volta Basin is the fact that
most of the hydropower is generated in the downstream areas, at Akosombo close to
the outlet of the basin, and at Bui dam in the near future. This high demand for water in
the downstream reaches of the Volta Basin stands in conflict with upstream watershed
development and interventions. Among the challenges for conducting research in the
Volta Basin are the poor physical infrastructure, the data-poor environment, and weak
human and institutional capacity.
GLOWA Volta is hosted at the Center for Development Research (ZEF) at the University
of Bonn, and is conducted in close collaboration with research partners in Europe, the
United States of America, and West Africa. GVP is conceived as a nine-year, multi- and
trans-disciplinary study organized in three phases. Phase I (June 2000 – May 2003)
emphasized the identification of methods and models; the establishment of research
infrastructure on the ground in Ghana, the collection of baseline climatic, hydrological
and socio-economic data, and the training of the first cadre of physical and social
scientists from the Volta Basin and surrounding regions of West Africa. In Phase II (June
2003 – May 2006), emphasis shifted from scoping studies and data collection to the
development, testing and application of a range of numerical simulation models; as well
as process-oriented studies of important bio-physical and socio-economic phenomena.
17
Phase III (June 2007 – May 2009) focused on the integration of Phase I and II outputs,
emphasis on aggregate economic analysis, operationalization of Decision Support
System (DSS) components and transfer of activities and responsibilities to institutions
within the Volta Basin.
This report is intended to provide a summary of research results achieved and activities
conducted in the third phase of the GVP.
1.1 Objectives and Structural setup of research clusters
The central objective of the GLOWA Volta Project (GVP) is the analysis of the physical
and socio-economic determinants of the hydrological cycle in the Volta Basin in the face
of global climate change. The main challenges for research and water management are
the climatic variability within the basin, limited spatio-temporal data coverage for climate,
hydrology, and land use data, as well as the heterogeneous institutional and socio-
cultural environment. Key aspects of the GVP research include sampling strategies and
scaling techniques to bridge data gaps, and the development of models on land use and
land cover change, water supply and demand, and to simulate human-environmental
interactions. Through interdisciplinary research, the project aims at supporting
sustainable water resource management in the Volta Basin, providing an integrated
assessment of environmental change and its impact. The main aim is the development
of “Decision Support Resources” that will help the authorities in Ghana, Burkina Faso,
and the other riparian countries to optimize water allocation.
The overall objectives of GVP, throughout all three phases, were
to provide an analysis of the physical and socio-economic determinants of the
hydrological cycle within the Volta Basin, and
to develop a scientifically sound Decision Support System (DSS) for the
assessment, sustainable use and development of the Basin‟s water resources.
Although not implicitly stated as an overall objective in the proposals of the Phases I to
III, capacity development (human capital) was an additional, elementary cornerstone of
the project. Capacity building and knowledge transfer have been pursued throughout the
project by conducting much of the research with students and researchers from the
Basin, and close collaboration with the GVP research network of Ghanaian and
Burkinabe counterparts.
While the project Phases I and II were organized along the research clusters
18
“Atmosphere”, “Land use”, and “Water use” to reflect the research foci of the Project, the
project structure was re-organized for Phase III to better match the more operational
requirements of the third project phase. The structuring of the research clusters and
work packages was changed to reflect the priorities placed on the integration of Phase I
and II research results, knowledge, data and tools, to set greater emphasis on economic
analysis at aggregated and sectoral levels, and to shift the orientation from research to
operational modes, emphasizing on the delivery of services described in previous
phases of GVP research.
In Phase III, the project was organized along the clusters “Water Supply and
Distribution” (Cluster S), “Analysis of Long-Term Environmental Change” (Cluster E),
“Water Demand” (Cluster D), “Consortium Building for Technology Transfer” (Cluster C),
and “GLOWA Volta Decision Support System” (Cluster I).
Figure 1: GLOWA Volta Phase III Research Clusters
The Analysis of Long-Term Environmental Change (E) cluster focuses on
environmental changes endogenous to the Volta Basin that evolve over decadal time
scales. These changes, such as alterations in land cover, soil degradation and loss of
wetlands reflect complex interactions and feedbacks between climate, human settlement
19
and economic activities. Cluster E carries forward much of the work conducted within
the previous Land Use cluster. Primary objectives are (i) to provide credible future land
cover scenarios required by climate and hydrology models, and (ii) to provide decision
support tools for proactive land management on the local and basin scales. The cluster
components cover the Automated Classification of Remotely Sensed Images (E1),
Cellular Automata (E2), GVP-LUDAS (E3), and Land-use Change Predictions and Land-
use Policy (E4).
The Water Supply and Distribution (S) cluster encompasses the analysis of physical
water distribution and availability in space and time, inclusive of atmospheric, surface
and subsurface hydrologic processes. It contains most of the elements of the previous
Atmosphere cluster, runoff and hydraulic routing models, and is extended to include the
analysis of climatic and hydrologic phenomena and investigation of groundwater
recharge. Cluster S consists of four subprojects, Hydrometeorological Modeling (S1),
the Hydrometeorological Observatory (S2), Remote Sensing and surface energy
balance (S3), and Surface, Soil and Groundwater monitoring (S4).
The Water Demand and Management (D) cluster consists largely of integrative
activities that build extensively on research conducted within Phase II on operations
research modeling of water-demanding economic sectors. It integrates Phase II work
packages on Water and Livelihood, Institutional Analysis, Household Decision-making
and Policy Response, the White Volta Policy Pilot, Policy Dialog at Basin Level, and
some aspects of Technical Integration of Socio-Economic and Environmental Modeling
Sub-Systems. The demand cluster has three components: Agricultural Water Demand
(D1), Non-Agricultural Water Demand (D2), and an Integrated Demand Simulation
framework (D3)
The fourth research cluster is Consortium Building for Technology Transfer (C): The
success of the GLOWA Volta Project will ultimately be measured by the continuity of
activities within the region following completion of GVP. GVP has built an effective
network of partners in Ghana and Burkina Faso, as well as a consortium of international
organizations including KACE, IWMI and UNU. During Phase III these three institutions
will progressively assume leadership of project activities, with the ultimate objective of
transferring ownership to capable institutional partners within all 6 riparian states.
Cluster C covers Knowledge Exchange and Participatory Decision Support (C1),
Transboundary Water Management (C2), and Consortium building, Training and
Outreach in use of DSS (C3).
20
The final cluster, GLOWA Volta Decision Support System (I) encompasses technical
activities required for the implementation of a scientifically sound DSS. DSS encompass
a wide range of scientific simulation tools embodying various methodological
approaches and technologies. However, there are several reasons why DSS are not
often used effectively at the management level, including lack of user-friendly interfaces,
insufficient involvement of potential end-users in software development, poor
identification of user needs and lack of adequate system infrastructure. The primary goal
of cluster I is to facilitate the development of an effective, user-friendly DSS
infrastructure for water management in the Volta Basin. In the third project phase, the
GVP has consolidated a multi-level GLOWA Volta Decision Support approach (Figure
2), which provides different sets of decision support at the scale appropriate to address
the problems. Cluster I covers Requirements Engineering (I1), GVDSS infrastructure
(I2), and GVDSS Workbench (I3).
Figure 2: The GLOWA Volta Decision Support Resources
21
1.2 Capacity Building
Capacity building is the process of developing and strengthening the skills, abilities, and
resources that organizations and communities need to survive, adapt, and thrive in the
fast-changing world (after Philbin 19961). “A fundamental goal is to enhance the ability to
evaluate and address the crucial questions related to policy choices and modes of
implementation among development options, based on an understanding of
environment potentials and limits and of needs perceived by the people of the country
concerned"(UNCED, 19922).
The capacity building in the GLOWA Volta Project focused on three main pillars, the
development of Human Capital, of Infrastructure and Technological Capacity, and the
development of Institutional Capacity. These three capacity building activities contribute
to the evolvement of an “enabling environment”, in which the riparian states are able to
make informed decisions over the resources of the Volta Basin.
Figure 3: GLOWA Volta Students
1 Philbin, A. (1998). Capacity Building Work with Social Justice Organizations: Views from the Field. Submitted to
A. Romero, Director, Human Rights and International Cooperation, The Ford Foundation.
2 UNCED (1992). Agenda 21. The United Nations Programme of Action from Rio.
22
The development of human capital has been a major component of the GLOWA Volta
Project. Over the whole length of the project, the research was heavily student based.
The largest part of the overall 81 students originated from the Volta Basin riparian
countries (44), with the second largest group of students coming from Germany (28).
Additional students who contributed to the GVP came from East Africa (4), the
Netherlands (3) and the United States of America (2). Most important for the
development of human capacity is the fact that 84% of the African graduate students
returned to Africa, where they have assumed academic and institutional positions.
In addition to the education of students, GVP has conducted a series of workshops and
trainings in the Volta Basin. In the past 2 years alone, 18 workshops and trainings have
been held in the Volta Basin, reaching several hundred participants and trainees - from
framer to scientist to policy makers – providing technical training, impact assessment,
and coping strategies.
Infrastructure and Technological Capacity Building was built in a number of different
aspects. A major contribution is the GLOWA Volta Geoportal, a multi-functional platform
to share and manage data and metadata, and for interactive mapping. It is the first
comprehensive, openly accessible database in the Volta Basin that provides the
platform for structured sharing of geospatial data. The range of other models given in
Figure 2, which are described in detail in the respective sections of the following report,
are referred to here as well.
Other contributions to infrastructural and technological capacity building are the network
of tele-transmitted river gauges, which allow obtaining instantaneous runoff
measurements in the basin, and the Biophysical Observation Network (BON, operated
in cooperation with the BIOTA West Project), a network of micro-meteorological stations
set up in a north-south and an east-west transects. Besides using the data obtained in
these networks for the calibration of models, the operation of these networks also
contributed to the human capacity building through involving of local staff.
Institutional Capacity building may be among the most challenging endeavors in the
framework of a research project. In the course of the third project phase, the GVP, as
one of the first partners, supported the evolving Volta Basin Authority (VBA). The VBA is
a river basin authority with transnational mandate for the Volta Basin which seeks to
promote Integrated Water Resources Management, to promote consultation tools
among parties for the development of the Basin, and to authorize the development of
infrastructure with substantial impact on water resources. The VBA has evolved to an
important partner, and it will play an important role in addressing the transnational
23
management of the Basins natural resources. Besides the engagement with the VBA,
the GLOWA Volta Project provided research support and maintained close links with the
Water Resources Commission (WRC) in Ghana.
Figure 4: The GLOWA Volta Research Network
In addition to the collaborations with the VBA and the WRC, the GVP has continued to
strengthen its research network of European, African, and American partners. The
continued collaboration not only focused on a north-south linkage, but also fosters
south-south collaboration, especially in conjunction with the returned students which
have developed interdisciplinary skills during their training.
24
1.3 Project Presentation and Media Coverage
In the course of the third phase, the project web page (www.glowa-volta.de) was
completely revised and remodeled. The information was updated to reflect the latest
developments in the project, and its structure was changed to reflect the re-organized
project structure that was adopted in Phase III of the project. In addition to the updated
information in the different clusters and the addition of the latest thesis and publications,
the above mentioned GLOWA Volta Geoportal was made available through the projects
web page.
In addition to the projects presentation on the internet, the GLOWA Volta Project has
contributed to BMBF brochures (GLOWA – Global Change and the Hydrological Cycle3,
and IWRM - Integrated Water Resources Management: From Research to
Implementation), and produced flyers for concise information on the project which were
distributed both in Europe and Africa.
In August 2008, the International Conference on “Global Change and Water Resources
in West Africa” was held in Ouagadougou, Burkina Faso, where the African GLOWA
projects, GLOWA Volta and GLOWA Impetus, presented their research results. The
GLOWA Conference was well attended and received international media coverage. In
conjunction with the conference, the Center for Development Research organized a
journalist trip to the Basin during which German journalists were able to experience the
region and gather information on the Volta Basin and its problems, mainly as they are
perceived by the local population. An exchange between German and African journalists
was also facilitated. As a result of the status conference, the journalist trip, local capacity
building efforts and presentation of research results, a number of newspaper
publications and radio features were published4, providing a broad audience with
information on the Volta Basin and the GLOWA Volta Project.
3 IHP/HWRP-Berichte, Heft 8, Koblenz 2008
4 The Chronicle (Ghana) - Drip Irrigation is the Most Efficient - Roy Ayariga (07.04.2008),
SWR contra – Wann kommt der Regen? Wettervorhersage für Westafrikas Bauern (14.08.2008),
Domradio Köln - Interview mit Wolfram Laube zu GLOWA (18.08.2008),
BBC - Global Change in Water Resources in West Africa (26.08.2008),
Africatime.com/Burkina - Gestion des ressources en eau: les projets "GLOWA" pour minimiser les effets du
changement climatique (26.08.2008),
Fasozine - Changements climatiques: La Partition de GLOWA (26.08.2008), L’Observateur Paalga - Changement
climatique et gestion de l’eau. Les Allemands font recours à la science (26.08.2008),
Le Pays Burkina Faso - Changement climatique et gestion de l’eau. Les resultants concluants du Programme
25
As in the previous two phases, the GLOWA Volta Project participated in numerous
scientific workshops and presented its ongoing and completed research at conferences.
Besides the theses of which most are available from the GLOWA Volta webpage, the
GLOWA Volta Project has authored more than 200 scientific publications, with a few
more to come.
GLOWA (26.08.2008),
General-Anzeiger Bonn - Wetterextreme in Afrika (26.08.2008),
Deutsche Welle - L’eau au centre des préoccupations à Ouagadougou (27.08.2008),
Deutschlandfunk - Forschung Aktuell: Launische Regenzeit. Im südlichen Westafrika verschieben sich die Regen-
und Trockenzeiten (29.08.2009),
Deutsche Welle - Tribune (09.09.2008),
ARD - Mehr Dürren, mehr Fluten: Klimawandel in Westafrika (September/Oktober 2008),
Deutsche Welle - Reportage Spécial (03.10.2008),
Süddeutsche Zeitung - Unser Dorf ist immer in Gefahr (04.10.2008),
SWR2 – Planet Erde: Teures Trinkwasser für Sirigu (07.10.2008),
SWR2 – Planet Erde: Wie sich die Bauern im Voltabecken auf den Klimawandel einstellen (02.12.2008),
SWR2 – Wissen: Wann kommt der Regen? Westafrikanische Bauern und der Klimawandel (13.01.2009),
WDR5 - Aus dem Takt - Klimawandel im Voltabecken (17.02.2009),
Radio KölnCampus – Das GLOWA Volta Geoportal für Westafrika (02.07.2009),
Magazin-Deutschland.de - Better Protection against Crop Failure (07.07.2009)
26
2. Achievements and research results of the sub-projects
2.1. Completed work from Phase II Clusters and ongoing projects
which contribute to several clusters
Due to changes in the project structure at the beginning of the third project phase, some
research activities cannot directly be summarized under the following project clusters. A
number of PhD projects, which started in Phase II, were completed in Phase III. This
section also incorporates projects which contribute to several clusters.
Research activities of A. Brunner for the dissertation ”Modeling soil erosion and
reservoir sedimentation at hillslope and catchment scale in Burkina Faso”, focused
mainly on (I) the evaluation of soil erosion results at hillslope scale and (II) the
assessment of reservoir siltation at catchment scale.
I At hillslope scale, on-site effects of soil erosion have been measured at two research
sites in southwestern Burkina Faso. Soil erosion is a major factor for the loss of nutrient-
rich topsoil from hillslopes and can cause severe agricultural problems. The continuous
loss of topsoil may lead to diminished soil fertility and hence to reduced crop yield, which
is particularly serious in countries dependent on agriculture for food production.
Therefore it is necessary to quantify soil loss and to identify adequate land management
strategies to prevent topsoil from being eroded. Three specific methods are applied at
hillslope scale to analyze soil erosion: I.I catenary soil sampling, I.II 137Cs-
measurements and I.III erosion simulations by the Water Erosion Prediction Project
(WEPP)- model.
I.I For catenary analysis, the suitability of the catena concept for soils in south-western
Burkina Faso was examined by soil profiles investigations and soil horizon description at
two research sites. The specific objectives are i) to assess catenary soil development
along hillslope transects, ii) to evaluate variations in physical and chemical soil
properties along these transects and, iii) to derive a soil profile dataset based on distinct
catenary hillslope units.
I.II The 137Cs technique is a more recent, but promising method to quantify soil erosion
and deposition over the landscape by measuring the remaining concentration of 137Cs in
the soil.
This environmental tracer technique can provide mid-term erosion rates (over
approximately 40-50 years) and gives information about the quantity of soil which is
27
eroded, re-distributed and finally accumulated downslope. The specific objectives of the 137Cs approach are i) to quantify the amount of soil loss and soil deposition at two
hillslopes, and ii) to evaluate the soil redistribution pattern of 137Cs derived from different
conversion models (proportional model, mass balance model 1 and 2).
I.III The physically-based Water Erosion Prediction Project (WEPP)-model was selected
to predict long-term soil loss rates along hillslope transects and to account for
horizontally distributed soil erosion processes. The specific objectives of the soil erosion
modeling approach are i) to simulate soil loss and soil deposition rates on two hillslope
transects, ii) to predict the effect of soil and water conservation as well as land
management techniques (e.g., minimum tillage, residue management, and contour
farming) on simulated soil loss and, iii) to compare simulated soil loss values with 137Cs
estimates along these transects.
II At catchment scale, the off-site effects of soil erosion such as the siltation of dams
have been assessed at two small reservoirs in southwestern Burkina Faso. Dams have
the function to store rainfall and runoff water from the catchment and serve as water
storages for domestic use, livestock and irrigation. At the same time, dams present
major sinks for sediments from upstream. Incoming and accumulated soil particles can
lead to severe changes in reservoir morphology, which will influence in return water
storage capacity and water use potential. In Burkina Faso, 850 dams have been
constructed, most of them with a water capacity below 1 Mm³. Especially these small
reservoirs are severely affected by storage losses. Therefore, several environmental
methods were applied to quantify siltation rate at catchment scale: II.I bathymetric
surveys, II.II sediment core analysis including 137Cs measurements and II.III sediment
simulations by the WaTEM/SEDEM model.
II.I The bathymetric survey is based on a comparison of changes in reservoirs bed
morphology. While a topographical map of the construction date provided information
about the initial morphology, the actual morphometry was measured by water-depth
measurements using a depth-sounder with mapping GPS unit sonar attached to an
inflatable boat (see Figure 5). The specific objectives are i) to monitor changes in water
storage volume by comparing the initial with the actual morphometry of the reservoirs
and ii) to calculate the thickness of accumulated sediment along a longitudinal cross-
section of the reservoir and iii) to estimate the “half-life” time of the reservoir.
II.II The retrieval of sediment cores from the bottom of the reservoir was found to be a
feasible approach to quantify the thickness of the accumulated sediment by stratigraphic
changes in soil properties and 137Cs concentration with depth. Sediment cores of up to 1
m length were taken from the bottom of the reservoir by a sediment core sampler (type
28
Beeker sampler). The specific objectives are i) to analyze downcore variations in
chemical and physical soil properties as well as 137Cs measurements and ii) to
reconstruct the maximum sedimentation depth and iii) to calculate sediment yield, trap
efficiency and annual sedimentation rates.
II.III The spatially distributed soil erosion and sediment delivery model WaTEM/SEDEM
was used to simulate annual soil loss and sediment delivery into small dams. The
specific objectives of the sediment modeling approach are i) to identify the most affected
erosion and deposition zones (sediment source and sediment sink areas) of three small
catchments, ii) to quantify the amount of soil deposition and to calculate sediment
delivery rates into the reservoirs and iii) to compare simulated results with those from
bathymetric surveys, sediment core analysis and 137Cs measurements.
Figure 5: Digital elevation model of a small reservoir in southwestern Burkina Faso based on bathymetric
measurements
29
I Results at hillslope scale:
I.I In terms of soil catenary development, the description of soil profiles indicates that
diagnostic soil properties are closely related to pedogeomorphic processes ascribed to
individual hillslope positions. The dynamic interaction between soil formation and
landform characteristics confirms furthermore the concept of catenary soil development
as it was first developed by Milne (1935) for soils in East-Africa and further specified by
Conacher and Dalrymple (1977) in the nine-landsurface model. The soil-landscape
description of two catenae in south-western Burkina Faso has shown, that these land
surface units show typical slope geometry and inherent diagnostic soil characteristics,
such as eluviated horizons, leaching, water retention or hydromorphic features.
Furthermore, also chemical and physical soil properties follow the catena concept
although their pattern downslope is not always clearly pronounced. The soil nutrient
status at two research sites is very low and highly deficient for soil available P. This
might be due to the negative nutrient balance which has been often reported for soils of
sub-Saharan Africa. Often, more nutrients are taken up by plants and lost by harvest
than have been replenished by fertilizers or nutrient recycling such as straw mulch or
compost. The use of mineral fertilizers is recommended in such environments and
moreover seen as indispensable to improve soil fertility and to ensure an adequate crop
yield. In terms of soil erosion modeling, it is therefore seen as useful to consider at least
three distinct catenary slope units, namely summit, shoulder/backslope and
footslope/toeslope position.
I.II The 137Cs approach is based on a comparison between the local reference inventory
collected from an undisturbed, non-cultivated and stable site and 137Cs samples
collected from hillslopes. Related to the reference inventory of 730 Bq m-2 (Bq =
Becquerel), all 137Cs values lower than the reference value indicate a loss and hence net
erosion, whereas all 137Cs values higher than the reference value represent a gain and
hence net deposition. At a hillslope in Dano, Burkina Faso, soil redistribution rates show
that erosion rates can reach up to 44 ha-1yr-1 at the summit and shoulder position
whereas deposition rates can reach up to -36 t ha-1yr-1 at the footslope/valley position. At
the hillslope in Wahable, the amplitude between erosion and deposition rate is even
higher with erosion rates of 56 t ha-1yr-1 at the shoulder position and deposition rates of
up to -88 t ha-1yr-1 at the footslope/valley position. However, when calculating net
erosion rates for the entire hillslope, results show values between 2.4 and 3.3 t ha-1yr-1
for the hillslope in Dano and between 2.7 and 5.0 t ha-1yr-1 ha yr for the hillslope in
Wahable. This indicates that although the averaged amount of soil loss is within a
tolerable range, some parts of the hillslope are severely affected and highly prone to
erosion. The identification of these affected hillslope areas allows to select more site-
30
specific management options in order to reduce the erosion risk and hence the amount
of nutrients lost from these endangered parts.
I.III Simulated soil loss predicted by the physically-based Water Erosion Prediction
Project (WEPP)-model shows also high differences in soil loss rates at individual
hillslope positions. Annual soil erosion rates are calculated for individual transects and
can reach at the hillslope of Dano up to 200 t ha-1yr-1 at steeper backslope positions
whereas deposition rates do not exceed 30 t ha-1 yr-1 at footslope/valley positions. At the
hillslope in Wahable, simulated erosion rates are lower and vary between erosion rates
of max. 11 t ha-1yr-1 and deposition rates of 16 t ha-1 yr-1. The differences in simulated
soil loss between both sites might be explained by models sensitivity to both
topographical conditions, such as higher slope gradients and to differences in soil
properties, such as soil texture, organic matter content and hydraulic conductivity.
However, although similar erosion rates between 10 and 200 t ha-1 yr-1 have been
reported for the Savanna ecosystems in West Africa, absolute soil loss data should be
considered with care. Considering land management options, WEPP-model simulations
have shown that at steeper hillslope positions (such as shoulder and backslope
position), the application of stone lines, minimum tillage, contour farming and residue
management could reduce soil loss by up to 95 %, 70 %, 55 % and 45 % respectively,
whereas burning and tillage by chisel plow could aggravate soil loss by maximal 250 %
and 600 % compared to the actual land management practices. This indicates that
especially at erosion-prone hillslope positions, adequate land management options
could highly reduce the risk of soil erosion.
Figure 6: Spatial pattern of soil erosion and deposition at a hill slope in south-western Burkina Faso based on
a 137
Cs conversion model
Mass-balance model 2
Stable
Ero
sio
nD
epositio
n
Superelevation of relief (3x)
Soil redistribution rate
(t ha-1 y-1)
-36
-32
-28
-24
-20
-16
-12
-8
-4
0
4
8
12
16
20
24
28
Mass-balance model 2
Stable
Ero
sio
nD
epositio
n
Superelevation of relief (3x)
Soil redistribution rate
(t ha-1 y-1)
-36
-32
-28
-24
-20
-16
-12
-8
-4
0
4
8
12
16
20
24
28
31
II Results at catchment scale:
II.I A comparison between the initial and actual stage-storage curves shows that the
reservoirs in Wahable and Fafo diminished their water volume by 30-50 % since the
time of construction. A loss in storage capacity of 50 % implies that the “half-life” of the
reservoir has been reached. The concept of “half-life” expresses the time required to
infill half of its original capacity. The half-life concept is an indicator of the time frame in
which sedimentation may seriously affect water supply and flood control, although it
does not indicate in return half of the time to reach complete sedimentation because
sediment trapping declines with reduced storage capacity. Both reservoirs in Wahable
and Fafo experienced approximately 20 years of sediment accumulation by wind and
water erosion and results indicate that they are losing their capacity at annual rates
ranging from 0.4 to 2.4 %. It is obvious, that the continuous siltation and reduction in
water storage capacity will severely affect water availability and its efficient use for
irrigation agriculture in the dry season.
II.II Results of the sediment reference profiles show clear downcore variations in soil
properties and 137Cs measurements and indicate a significant stratigraphic change at
the depth when the initial reservoir bed is reached. The accumulated sediment layer in
Wahable had a thickness of 40 to 45 cm, whereas the one in Fafo had a thickness of 20
to 25 cm. This indicates an average gain in the sediment layer of approximately 1 to
2 cm per year, which can be interpreted as already critical in relation to the shallow
depth of 1.5 m to max. 3 m at the peak of the rainy season. As it is technically difficult,
cost-intensive and not feasible for most sites in Burkina Faso to recover the capacity of
these small reservoirs by dredging or hydraulic flushing, control measures and
prevention methods become more and more important. The use of soil and water
conservation methods on farmers‟ fields (e.g. stone lines, vegetation barriers, contour
plowing) and the construction of intermediate check dams at most affected runoff and
sediment flow pathways, could be one option to counteract soil loss at its initial source of
origin.
II.III Simulations by the WaTEM/SEDEM model produced spatially explicit erosion and
deposition maps for each point of the catchment. Additionally sediment delivery rates
into channels, rivers and finally into the reservoirs of the catchment were calculated.
Average net soil erosion rates at catchment scale reached 2.5 t ha-1 yr-1 whereas
average net deposition rates had values of 2.3 t ha-1yr-1. Sediment deposition occurred
mainly along the flow network, in depressions and sink areas where eroded soil from
upslope was accumulated. For the calibration of the model, results from the bathymetric
survey and the sediment core approach were used in order to adjust the transport
capacity coefficient of the model against measured sediment yield data from the dams.
32
For soil erosion predictions in West Africa, the WaTEM/SEDEM model was found an
adequate tool to represent the spatial distribution of soil loss and the deposition of
sediment yield into small reservoirs.
The research of T. Frazier establishes a means to project energy demand for Ghana‟s
most significant area of consumption, the Greater Accra Region. Sub-Saharan Africa is
urbanizing more rapidly than any other region in the world and at a historically
unprecedented absolute rate of increase. The current growth rate of almost 5 percent
per year implies close to a doubling of the urban population in 15 years, with new urban
residents projected to rise sharply by over 300 million between 2000 and 2030 (Figure
7). Urbanization implies potential harms, but it could also be positive and beneficial.
Improved infrastructure is a significant component of promoting smart growth in African
cities, while planning for improved land use controls and electricity facilities are
important first steps towards effective cities that promote increased GDP, average
annual income, and an enabling environment for economic development and poverty
reduction. Focusing on electricity provisions in the cities of the sub-Sahara is also
important because urban areas in the developing world are projected to overtake OECD
countries as the largest emitters of GHGs5.
Figure 7: Urban and Rural Growth in Africa
5 Kessides, C. (2006). The urban transition in Sub-Saharan Africa: implications for economic growth and poverty
reduction. The Cities Alliance, The World.
33
In step with its sub-Saharan location, Ghana is also experiencing unprecedented
urbanization with approximately 50 percent of its more than 20 million people currently
living in urban areas. This share is expected to be 65% by 2030 (Figure 8). The most
significant growth is taking place in Accra, which is Ghana‟s administrative and
commercial center, as well as its largest and fastest growing urban concentration.
Inhabited by more than 3 million people, representing 15 percent of the total population
and 40% of Ghana‟s total urban population, Accra‟s growth rate of 4% per year implies
that the population will double in 16 years. These projected increases are not a new
trend, instead they are an extension of the past 15 years, when Accra‟s population
doubled and its area expanded almost three fold. Between 1990 and 2005 the built up
area increased from 133 square kilometers to 344 square kilometers, and the population
density decreased from 14,000 persons per square kilometer to 8,000 (United Nations,
2005; World Bank, 2007; World Bank, 2009).
Figure 8: Urban and Rural Growth in Ghana
This concern for the rapid growth of urban areas in the developing world is one of the
major driving forces behind the immediate need to develop sophisticated quantitative
models for projecting land use and electricity demand under different scenarios. Unlike
land use planning in Europe and North America, the cities in Africa exist without the
benefit of a land titling system, a functioning taxation system, building permitting and
inspection or zoning. Electricity planning does not incoproate rights of way functional
classifications and development controls appropriate for land use and location prior to
34
distribution. The location and placement of electicity transmission, distribution and other
appurtenances is often unknown and unregulated. Almost no comprehensive planning
has taken place in African cities which promotes sustainable development planning
within the context of the ever expanding metropolis of Accra.
Figure 9: Sprawl of Accra, Ghana from 1985 until 2000
This research has proposed to fulfill a number of needs that have not been met,
particularly within the arenas of Urban and Regional Planning, Electricity Planning, and
Urban Development Research.
Until now, no known example exists of a plot (parcel) based, urban simulation
system of a major city in Africa. This work presents a comprehensive urban
simulation system of Accra, Ghana, a major economic and social center in West
Africa with more than 3 million inhabitants (Figure 9).
No known example exists in West Africa of a land use based, electricity
forecasting model, for a major urban area in West Africa (1 million or more
people). This work presents a comprehensive electricity demand model which is
fundamentally based on land use and performance standards at the plot level for
an urban area of more than 3 million people.
35
No known example exists of a plot based, urban simulation system for projecting
scenarios and illustrating the implications of different public policies of a major
city in Africa. This work presents land use and transportation scenarios for Accra,
Ghana in terms of low, medium, and high population and economic growth rates
and in terms of business-as-usual or potential weak, moderate and strong
sustainability policy cadres.
The primary goal of this work was to develop an urban simulation system that will
forecast probable land development patterns in the Greater Accra Region under
different policy and growth scenarios for the next 20 years. To this effect, answering the
following questions have been central objectives of this work:
Which land development patterns are most likely in the Greater Accra Region
over the next 20 years if development continues in terms of „business-as-usual‟?
What are the projected electricity demands and expected level of services for all
major distribution facilities throughout Greater Accra Region?
Which sets of policies, regulations and controls will be the most cost effective in
advancing a sustainable land use and electricity use plan in the Greater Accra
Region?
This research has relied heavily on the Open Platform for Urban Simulation (OPUS)
which was developed by Paul Waddell and his development team at the Center for
Urban Simulation and Policy Analysis (CUSPA) at the University of California, Berkeley.
UrbanSim makes extensive use of modeling individual actions, based on the theory of
Random Utility Maximization pioneered by McFadden6 in the 1970‟s. This discrete
choice approach has been used to derive a model based on the probability of a set of
available alternatives, the characteristics of the chooser, the attributes of the
alternatives, and the proportional relative utility of that chooser‟s alternatives (Figure 10).
Maximum likelihood and simulated maximum likelihood methods to estimate the
parameters of these choice models have been derived from data on revealed or stated
preferences, using a wide range of structural specifications (see Train, 2003)7.
6 McFadden, D. (1974). “The measurement of urban travel demand.” Journal of public economics 3 (4): 303.
McFadden, D. (1981). “Econometric models of probabilistic choice.” Structural Analysis of Discrete Data with
Econometric Applications: 198-272. MIT Press, Cambridge, MA.
7 Train, K. E. (2003). Discrete Choice Methods with Simulation. Cambridge University Press.
36
Figure 10: Software Package Relationships
The components of UrbanSim are models which input base-data in terms of household
characteristics, persons, and jobs, simulate the real-world actions of agents acting within
an urban system, then update base-data as annual cycles progress (Figure 11).
Developers construct new buildings or redevelop existing ones. Buildings are located on
land parcels that have particular characteristics such as value, land use, and area.
Within the simulation environment, governments implement a new policy such as the
imposition of building permitting and inspections, zoning or comprehensive planning, or
pricing policies such as development impact fees. Governments also build infrastructure,
including transportation facilities, which interacts with the distribution of activities to
generate patterns of accessibility at different locations that in turn influence the
attractiveness of these sites for different consumers. Households have particular
characteristics that may influence their preferences and demands for housing of different
types at different locations. Businesses also have preferences that vary by industry and
size of business (number of employees) for alternative building types and locations.
These urban actors and processes are implemented in model components that are
connected through the software implementation.
37
Figure 11: Annual Cycle of a Simulation Run
This urban simulation system is comprised of three primary parts: data, models, and
scenarios. There are five essential tables required to run the proposed urban simulation
system. These tables provide: economic and demographic characteristics of households
and the individuals living at that location; data about plots and their buildings including
the value and use; information about jobs and their associated industrial classification,
and point to point travel times by mode throughout the spatial environment. These tables
are employed by a number of models which also incorporate rates of mobility for
residential, commercial, industrial and institutional land use classifications. Finally, the
simulations are run as business-as-usual or in terms of sustainability approaches.
The research of T. Frazier has created a highly disaggregated, agent-based urban
simulation system based on plots (parcels) and buildings, including a comprehensive
electricity demand model for the Greater Accra Metropolitan Area (GAMA). A baseline
run (business-as-usual) comprised of models projecting household and business
decisions as well as land value and travel patterns was developed as a series of location
choice, regression, and simple allocation models. Household, person, and jobs tables
have been synthetically generated from 5% sample data from the Ghana Statistical
Service using the iterative proportionate fitting (IPF) method. These tables have been
incorporated into the Open Platform for Urban Simulation (OPUS), a runtime
environment, primarily written in python, with effective SQL database and GIS
38
interfaces, and linked with an electricity demand model programmed in Python. Several
large scale datasets (including rates of residential mobility) were obtained from the
Ghanaian ministries which describe Accra‟s physical and human geographical
environment. Additionally, weak, moderate and strong sustainability policy scenarios
have been developed and forecasted in terms of low, medium, and high economic and
population growth rates for the time period 2010 until 2030.
Figure 12: Round in Jamestown, Korle-Bu District illustrating Plot Land Value and Land Use (Green –
Residential; Blue – Commercial; Brown – Institutional; Government – Not Shown Here)
The following individual objectives have been achieved as part of the step by step
process of building the urban simulation system.
Synthetically generated household, person and jobs population tables using the
Iterative Proportional Fitting (IPF) method. This task depended on data already
obtained from the Ghana Statistical Service as well as additional data to synthesize
tables with an improved „goodness of fit‟ based on the methods developed by Ram
Pendyala at Arizona State University.
39
Improved the residential location choice model based on household and person
attributes and previously conducted surveys on residential mobility. This task
depended upon mobility rates obtained from the publication Residential Mobility in
the Greater Accra Region and collaboration with Monique Bertrand at the University
of Caen, France.
Spatially distributed these households in accordance with their location throughout
the Greater Accra area, and included typical household demographics. This function
was an integral part of the Open Platform for Urban Simulation platform developed
by Paul Waddell at the University of California Berkeley, USA. Spatial dimensions
and locations of plots and buildings have been acquired for the Greater Accra region
and were used in this work. It was necessary to further specify land use
classifications of plots and buildings beyond „residential.‟ Some indicator of density in
accordance with building type, such as compound house, self-contained house, or
flat, would improve accuracy for predicting residential mobility. (Figure 13)
Conducted a literature review on commercial location choice mobility rates. Some
means for determining job mobility rates in the developing world, and in particular
West Africa was needed. The informal economy comprises as much as 80% of the
labor force and is mostly misunderstood in terms of its working dynamics.
Spatially distributed these businesses in accordance with their location throughout
the Greater Accra area. As previously indicated the complete physical environment
of Accra, including transportation facilities and all buildings, has been projected and
incorporated into the urban simulation system. Land use classification of individual
plots have been identified in the scale of their ability to attract clientele (gravity as a
destination) as well as in accordance of attenuation of commercial uses (i.e. local,
neighborhood, district, region)
Simulated industrial location choice based on business attributes and located these
industries in accordance with their location throughout the Greater Accra area. This
was relatively simple compared to residential and commercial land uses since most
industrial land uses are easy to identify. Some attenuation of land use, such as light,
medium and heavy industrial was implemented.
Simulated institutional location choice throughout the Greater Accra area. Land use
classification included adding public safety facilities (police or fire), public health
facilities (hospitals and clinics), public education facilities (schools), and other
government buildings (national ministries, district councils, tribal headquarters).
Developed a comprehensive, land use based travel model. This task included
identifying the functional classification of all roadway facilities in the Greater Accra
Metropolitan Area and integrating into File Geodatabase for Greater Accra. A future
40
effort will be to incorporate a travel model based on MATSim, a framework for
implementing large-scale agent-based transport simulations, and integrated into the
OPUS operating environment. MATSim provides a means to develop demand
models, agent-based mobility simulations (traffic flow simulation), re-planning, a
controller for iterative simulation runs, and methods for analyzing output.
Incorporated demographic growth as an exogenous variable in order to project low,
medium, and high growth scenarios. This was a simple allocation model that is
incorporated into the SQL database as a table and then incorporated into the OPUS
operating environment.
Incorporated economic growth as an exogenous variable in order to project low,
medium, and high growth scenarios. This was also a simple allocation model for
incorporation into SQL and OPUS.
Developed Electricity Demand Model based on the historical demand of more than
500,000 accounts for the period from October 2006 until January 2008.
Figure 13: Plots of the Korle Bu District
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K. Nyarko´s doctoral research on the role of floodplain wetlands in hydrological
processes in the basin was carried out in Tindama and Pwalugu along the White Volta
River in the Upper East Region of Ghana. An examination of water flow within the
unsaturated zone based on infiltration experiments conducted in the Tindama and
Pwalugu wetland sites showed variability and, in most cases, high infiltration rates at the
start of the experiment followed by gradual decline over time. Exceptions existed due to
the breakdown of surface crust or reduction in the hydro-phobicity, which resulted in
increasing infiltration rate over time. In order to quantify the extent of floodwater storage
within floodplain wetlands and their contribution to subsequent river discharges, a series
of complementary studies was conducted utilizing stable isotopes, physical monitoring of
groundwater levels and numerical modeling. The variation in the isotope composition in
the river and wetland water samples, respectively, revealed the pattern of flow and
exchange of water between the wetlands and the main river system.
The completed PhD thesis (September 2007) used HYDRUS-1D model results as input
into the MODFLOW model to simulate interaction between floodplain wetlands and river
flow. The isotope tracers oxygen-18 and deuterium were utilized to derive a water
balance. Model results indicate a bidirectional relationship between floodplain wetlands
and river. They also show recurrent spatial and temporal patterns in the controlling
factors, such as horizontal hydraulic conductivity, specific yield and specific storage. In
applying the model, emphasis should be placed on the collection of temporally and
spatially high-resolution data.
The PhD project by L. Tia was defended in December 2007. In his work, he modeled
vegetation dynamics and investigated their contribution to the water balance in the Volta
Basin. Vegetation is recognized as an important component of the global climate system
through its control of energy fluxes over substantial portions of the land surface.
Moreover, it has been shown that vegetation-atmosphere interactions regulate local
weather and hydrological balances and regional climate. The study focuses on the
estimation of the contribution of tree stands to the surface water balance by means of
transpiration and actual evapotranspiration (ETa). The study used the nature reserve of
Bontioli (NRB) in southwestern Burkina Faso, from which it scaled up to larger areas
within the Volta Basin. This was achieved by modeling tree density and estimating daily
whole-tree water use rates. The method encompasses two components: (1) estimation
of climate, tree species and water-related variables, and (2) remote sensing and GIS
studies. The quantification of tree water uptake was achieved by the xylem
Heat-Balance method to assess sap flow rates of 17 tree species measured
42
continuously from April 2005 to December 2006. During this period, weather data were
recorded by Eddy Correlation and microclimate stations. Tree parameters were
collected on the ground according to biometric standard methods in order to determine
the phytosociology and the physiognomy of the vegetation cover. In addition, the LAI-
SEB model, based on remotely sensed spectral vegetation indices and the surface
energy balance outputs derived from the Aster image of November 2006, was
developed to accurately estimate tree densities. The results reveal that the NRB is
useful for biodiversity conservation because it provides a habitat for 71 (± 2) tree species
representing 19 families, typical for tree savanna (33 species), shrub savanna (39) and
gallery forest (10). The LAI-SEB model produced validated large-scale maps of (1) tree
density by stem count, (2) tree density by DBH estimates and (3) tree density by crown
cover estimates. The reliability of the model was proven through the comparison
between the mean absolute tree density (331 ± 4 stems ha-1) and the mean predicted
tree density (325 ± 87 stems ha-1). In the study area, the mean annual ETa was 94 % of
the rainfall in the dry year 2005 and 80 % in the wet year 2006. The mean daily whole-
tree water use rates ranged from 10.1 kg day-1 for Crossopteryx febrifuga to
492 kg day-1 for Pterocarpus erinaceus.
Those rates were influenced and regulated by weather conditions, specifically by solar
energy. Moreover, the field-specific mean daily tree stand transpiration was 0.7 mm
day-1; transpiration rates increased from dry to rainy seasons with highs between mid-
June and mid-September. The predicted tree stand transpiration map obtained by
means of the LAI-SEB model shows that 62.1 % of the map surface was not contributing
to transpiration, whereas 34.3 % of its surface transpired between 0 and 1 mm day-1.
The mean daily ETa was 3.6 mm day-1. The final analysis highlight that the contribution
of 8 large trees (DBH > 5 cm) to the water balance ranges from 9 to 20 % of rainfall,
depending on the vegetation type and the weather conditions. These results
demonstrate the importance of trees in the functioning of the surface water balance and
climate regulation through the maintenance of evapotranspiration in semi-arid regions,
particularly during dry seasons. Consequently, to mitigate drought, water scarcity,
poverty, threats to livelihood and food security one should start by preventing the
destructive effects of anthropogenic activities on vegetation covers. In this context,
decision-makers should advocate regional and concerted efforts to restore natural
vegetation through reforestation campaigns.
The completed PhD thesis by D.S. Kpongor on ”Spatially explicit modeling of Sorghum
production on a complex terrain in the semi-arid region of Ghana using APSIM” was
defended in May 2007. The thesis outlined that land-use trajectories have influenced the
43
nutrient stock of the soils in the study area. Furthermore, the impact of farmers‟
management activities on nutrient stocks was significant. Though a non-parametric test,
different soils were revealed, considerable variability could be observed within individual
soils based on their chemical and physical properties. The distribution of soil parameters
was influenced by the soils, farmers‟ management practices and topography. APSIM
predicted the grain yield response of sorghum to both N and P application with an
overall modified internal coefficient of efficiency of 0.64. A gradual decline in grain yield
was observed over the 29-year simulation period in both the homestead fields and the
bush farms, with yields being much lower in the latter. Applying mineral N fertilizer in the
homestead fields (50 % of the amount applied on the bush farm) with crop residue
incorporation produced average grain yields that were similar to those produced on the
bush farm. Temporal variability in grain yield was consistently higher with the removal of
crop residues in both management systems. APSIM is responsive to both organic and
inorganic fertilizer applications in the study area and also highlights the essential role of
crop residues and inorganic fertilizer in influencing the temporal variability in sorghum
grain production and hence the impact of farmers‟ management practices on food
security. The use of inorganic fertilizer and incorporation of crop residues (organic
matter) are critical for attaining food security.
After graduation, two further field experiments were conducted in Ghana using maize in
the minor rainy season of 2007. Experiments have been repeated in the major rainy
season of 2008. The results from these experiments are to be used together with soil
data and forecasted weather data from the GLOWA Volta Project.
The PhD project of J.-P. Sandwidi was successfully completed in October 2007.
Groundwater potential in the Kompienga dam basin within the Oti sub-basin of the Volta
River Basin was estimated using three methods: chloride mass balance, water balance
and water table fluctuation methods. The estimate shows that 5% of the annual rainfall
replenishes the basin aquifers of essentially crystalline basement. From this recharge
rate, a mere 2% is used as domestic water supply. Using pessimistic scenarios of
decreasing rainfall (up to 20% of the long term mean annual rainfall) in the basin and
increasing population along the coming years, it was shown that the domestic water
supply will remain satisfactory if a required number of hydraulic infrastructures are
provided. The national standard of water supply to rural areas is therefore suggested to
be increased in order to improve the supply; water resources development may
contribute to more income and livelihood improvement. Sandwidi´s results can be
summarized as follows: (a) groundwater potential in the basin: 5% of annual rainfall; i.e.
ca 44 mm; (b) water use by the population: 2% of the basin annual recharge in 2005; 76
44
l capita-1 day-1 (for all purposes); (c) water supply rate to the population until 2030:
variable according to the number of boreholes and wells in the basin and their average
unit yield that needs to be subsequently increased according to the increase in the water
demand; (d) recommended water supply rate in rural areas of Burkina Faso: 25 to 30
l capita-1 day-1 for the period of March to May; and (e) water resource development:
recommended respectively to the actual low level of water use in the basin in
comparison to the annual recharge. Small-scale irrigation schemes were suggested for
the development of the water resources.
B. Antwi completed the final write-up of his dissertation in March 2006. The objectives
of the study were to assess the long-term soil erosion rates under different land uses by
using 137Cs, 210Pb and particle size fractions (PSFs) as tracers, evaluate the
performance of some of the existing calibration models, establish the relationships
between the different tracers to facilitate the generation of uniform values irrespective of
the tracer used and finally, and to determine the spatial distribution of the tracer-derived
erosion rates and their implications on some parameters of topsoil quality.
The study was at GLOWA-Volta experimental site on longitude 001o 16/ W and latitude
07o 19 – 20/ N within the Volta Basin of Ghana. Soil and land-use data were collected
along grid points for spatial analysis. The data included 137Cs, 210Pb, infiltration rate,
hydraulic conductivity, particle size distribution, organic carbon, exchangeable
potassium, available phosphorus and rainfall. The calibration models were the
Proportional (CsPM), Mass Balance 1 (CsMB1), Mass balance 2 (CsMB2) and Diffusion
and Migration (CsDM) models for 137Cs, Mass Balance (PbMB) and Diffusion and
Migration (PbDM) models for 210Pb, clay ratio (CR), sand ratio (SR) and NUSLE (soil
erodibility from the Universal Soil Loss Equation (USLE) nomograph) for particle size
fractions. Variance reduction tools and Morgan‟s ratio were used to determine the
performance of the models.
Secondly, he applied research information he had acquired over the years to address
soil erosion problems in three communities from May to October, 2006. This was
sponsored by United States Agency for International Development (USAID) through the
Advents Relief and Development Agency International (ADRA), CSIR-Soil Research
Institute and Ministry of Food and Agriculture, Ghana. The technology application
involved assembling previous erosion control research results including those developed
at the GLOWA-Volta project site. We trained the communities on how to reduce
sediment flush to water resources using participatory methods (Figure 14). The
communities identified their major erosion problems and we were invited as resource
persons to assist the implementation of the project. The achievements were telecast on
45
national television studios.
The study determined the reference values of the tracers: 668 ± 90 Bq m-2 and 12680
1700 for 137Cs and 210Pb, respectively; SR was 0.99 0.13, CR (4.85 1.89) and
NUSLE (0.58 0.07). CsPM, CsMB1 and NUSLE predicted very low erosion rates
typical of fallow lands (≤ 1.0 Mg ha-1yr-1); PbDM, SR, and CR for moderate erosion
rates from a land rotation system (≤ 5.0 Mg ha-1yr-1) and CsMB2 and PbMB for high
erosion rates from intensively cultivated fields (≥ 5.0 Mg ha-1yr-1) .
The study established that the risk associated with predicting erosion rates was in the
order: CsPM (CV=85 %) < CsDM (CV=89 %) < CsMB1 (CV=95 %) < CsMB2
(CV=105 %) for 137Cs models; PbDM (CV=85 %) < PbMB (CV=92 %) for 210Pb models;
and NUSLE (CV=53 %) < SR (CV=63 %) for PSFs. The sensitivity analyses suggested
that losses in 137Cs and 210Pb with respect to the reference values were unstable beyond
40 %; however, SR, CR and NUSLE were stable beyond 50 % loss. Morgan‟s
performance ratio showed that the erosion rates by CsDM, PbDM, NUSLE, SR and CR
were reliable (0.5 - 2.0). The linear and robust linear regressions used to establish inter-
convertibility of the tracers suggested the scaling of point values with respect to the
reference to obtain a high relationship among the tracers.
Kriging was used to determine the spatial distribution of the erosion tracers and some
parameters of soil quality. The results suggest that 137Cs and 210Pb erosion rates reflect
the contribution of erosion to soil compaction while the movement of available
phosphorus and exchangeable potassium were linked to 137Cs and 210Pb distributions,
respectively. NUSLE and SR erodibilities were associated with the loss of organic
carbon content of the soil. The study recommends the use of 137Cs, 210Pb, SR and
NUSLE for monitoring the long-term spatial erosion rates in the Forest–savanna
transition ecology of the Volta Basin for sustainable land use planning.
46
Figure 14: Erosion control program at a village in the Volta Basin
For the Assessment of human-induced land degradation in Volta Basin from 1982-2003
Q. B. Le, L. Desta and P. Vlek conducted a step-wise analysis using a series of
databases to identify the extent of land under anthropogenic threats. By integrating time-
series of NDVI (Normalized Difference Vegetation Index) and rainfall from 1982 to 2002,
we delineated the geographic extents of zones with significant biomass decline or
improvement in the Volta Basin. To distinguish human-induced biomass trends from
climate-driven vegetation dynamics, we excluded those areas that had shown a strong
biomass response to inter-annual rainfall variation. Pixels with NDVI changes in
accordance with rainfall (positive correlation) were considered due to climate change or
variation. Pixels not affected by rainfall (no or negative correlation) are those where
green biomass change could be interpreted to reflect areas with strictly human induced
land degradation. Spatial data of soil constraints, land-use/cover and population density
within the study period were used to interpret possible underlying factors of land
productivity decline. The results of the study show that about 31 thousands km2 (8% of
the basin land mass), which is the living space of over 1.3 million people, was land that
is losing its ability to produce green biomass due to human actions. The degradation
areas for the various land cover types are 12.2 thousands km2 for woodland, 8.3
thousands km2 for agriculture, 7.3 thousands km2 for shrubland, and 1.6 thousands km2
47
for evergreen forest. The relatively low population density in the degraded areas
(averagely 43 persons km-2) would suggest that these are marginal areas with limited
carrying capacity to start with. As population pressure increases, more fragile lands will
be taken into cultivation leading degradation with below average population densities.
Correcting atmospheric fertilization effects in remote sensing-based assessment of land
degradation: Long-term trend analysis of biomass productivity (1982-2003) shows that
the greening areas are about 22% of the basin‟s land mass, which is much larger than
the areas showing significant biomass decline (8%). Moreover, about 81% of the
greening areas experienced no significant correlation to annual rainfall, showing that this
profound greening cannot be explained by rainfall dynamics. Global changes in
atmospheric chemistry, e.g. rising levels of atmospheric CO2 and NOx, are likely
responsible for the observed increasing trend in biomass. Evidences from other
continents on atmospheric fertilization, the observed NDVI improvements in SSA may
be plausibly explained by a shift in atmospheric chemistry. Assuming that atmospheric
fertilization is ubiquitous in SSA, the process would mask degradation of land due to
direct human activities. Against this background, a re-assessment of the vegetation
decline in the Volta Basin, taking into account atmospheric fertilization, increased the
land affected by human-induced degradation from 8 to 65%. The masked degradation
areas for the various land-cover types are 106 thousands km2 for agriculture, 55.5
thousands km2 for shrubland, 52.5 thousands km2 for woodland and 10.4 thousands km2
for arid grassland. At this rate of decline in land productivity, the basin may soon lack the
land resources necessary for economic development.
LAndscape Management and Planning Tool (LAMPT)to identify soil loss hotspots in
White Volta sub-basin: The Revised Universal Soil Loss Equation (RUSLE) and a
Distributed Sediment Delivery Model (DSDM) in a GIS environment to estimate the
spatial distribution of areas experiencing different levels of soil loss in the White Volta
Basin. The RUSLE is employed to map the spatial patterns of major sediment source
areas based on data calibrated for the study region. As RUSLE only estimates the
potential gross erosion of each grid cell, a DSDM is used to estimate the sediment
delivery efficiency of each cell using flow distance and velocity along the flow path. The
combined models allow a classification of sub-watersheds experiencing different levels
of soil loss using a soil tolerance threshold suitable for the study areas (Burkina Faso
and Ghana).
48
Figure 15: Screenshot LAMPT
The result shows that the majority of areas around north-eastern and eastern parts of
the White Volta Basin (mainly south-eastern Burkina Faso and Upper East Region of
Ghana) are associated with high levels of sediment yield (over 15 t ha-1 y-1). The main
reason could be high population pressure, poor surface cover and relatively high slope
of some of the areas in Ghana. On the other hand, the north-western and southern parts
of the basin experience low levels of sediment yield (less than 5 t ha-1 y-1) mainly due to
their flat terrain and good surface cover that encourage sediment deposition rather than
erosion. The study reveals that a GIS-based soil erosion and sediment delivery model
49
can successfully be used for identifying and prioritizing critical sub-watersheds for
management purposes. Such a tool can be of significance in developing areas where
problems are severe but resources are scarce.
LAndscape Management and Planning Tool (LAMPT) to facilitate land management
decision making and landscape planning by optimization: We integrated some of the
most commonly used soil erosion and deposition models into NetLogo, an agent-based
programming platform, producing a LAMPT‟s prototype. The operational model was
designed in such a way that fast and robust sensitivity analyses can be performed, after
users are allowed to (i) select and set different physical parameters, and (ii) choose
different sets of land-use management and planning options. The physical parameters
choice meets the scientific needs of landscape modelers in their exploration of adequate
values of the many parameters in soil/sedimentation models that are often not well-
calibrated in developing regions. The latter is expected to meet the needs of
practitioners in catchment management and planning. As the tool allows front-end users
to handle the selection of management/planning options, and provide a fast and
responsive outputs (in terms of both maps and graphs), LAMPT can assist in effective
multi-stakeholder negotiations over land-use planning where the minimization the
degradation of land/water resources is the ultimate goal. The LAMPT model can be
easily coupled with LUDAS, an agent-based land-use change model using the same
platform, to comprehensively simulate environment–community loops. During the further
development of LAMPT, the research team intends to follow a participatory approach to
enhance the relevance of the tool to local community needs. To plausibly calibrate
LAMPT at the catchment/community levels in the data scarce environment of West
Africa, additional long-term research catchments are essential.
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2.2 Cluster S Water Supply and Distribution
The cluster "Water Supply & Distribution" is designed to provide the primary physical
components of the integrated analysis of the hydrological cycle within the Volta Basin,
inclusive of atmospheric, surface and subsurface processes. It encompasses
probability-based analysis of climatic and hydrologic events made possible through
Phase II outputs, and a range of activities focused on the surface-soil water-
groundwater continuum. The emphasis within the theme is on the integration of ongoing
research activities leading to operational prototypes of water resources forecasting and
management tools which will be transferred to research partners within the basin.
The cluster includes research on: (a) the primary physical components of the integrated
analysis of the hydrologic cycle; (b) hydrological and climatological data; (c) all
resources and processes related to water (atmosphere, soil, surface, etc.).
Thus, the Water Supply and Distribution cluster aims at supporting near-term water
management decision making for stakeholders, e.g. economic project planning,
agriculture, policy, etc., to allow sustainable water use in the Volta Basin for the future.
2.2.1 Sub-project S1: Hydrometeorological Modeling (MM5 and WaSiM)
Focus of the research activities was the identification of objective weather patterns,
which are highly unfavorable for agriculture. Special attention is given to weather
patterns that tend to produce extremes in precipitation resulting in unusually wet or
droughty conditions.
Milestones achieved
Completion of interface for assimilation of satellite derived land surface
parameters (albedo, emissivity, LAI) into MM5 and WaSiM.
Coupled water balance simulations completed and validated for White Volta
catchment
Identification of pressure and SST anomaly patterns that indicate onset and
cessation of the rainy season
Methods and tools for onset/cessation estimation completed
51
Milestones achieved with deviations
Completion of uncertainty analysis of WaSiM output in the White Volta Basin
using Monte Carlo simulation:
Instead of Monte Carlo simulations more sophisticated methods, like external drift
kriging and turning bands were applied
Completion of CropSyst simulations to provide improved rainy season onset
(ORS) definitions
Crop yield data were not available for Ghana or Burkina Faso. Instead data for
Cameroon were used
Transfer of operational weather forecasting to KACE, Ghanaian Met Services
Training for operational weather forecasting was performed for two scientists of
Ghanaian Meteorological Service at IMK-IFU (Mr. Soami Pokperlaar and Mr. Juati
Aylari-Naa). Due to the fact that the speed of the internet connection at KACE
was not fast enough to retrieve operational global GFS forecasts (needed as
input for the regional forecast with MM5), transfer was not established. Weather
forecast is now performed at IMK-IFU and results are published operationally
under http://www.imk-ifu.kit.edu/wetter/index_wetter_africa.htm
Transfer and implementation of coupled model system on LINUX cluster at KACE
Training for MM5 and WaSiM performed with Dr. Barnabas Amisigo at IMK-IFU.
WaSiM was transferred during training courses in Accra and Ouagadougou.
Identification of statistical models of risk of extreme events; regionalization of
models
This milestone was addressed by Raimond Kasei in combination with sub-project
S2
Milestones not achieved
Completion of 2x30 years time slices of ECHAM4 A2 and B2 scenario runs in
27x27 km² resolution for West Africa, both for land use 1990 and 2000.
This topic and this PhD position was not part of the IMK-IFU contract. No PhD
student could be recruited to pursue this investigation.
Methodology and Research Results
Sustainable water resources management under increasing water demands and
changing climate conditions is a central, socio-political challenge, in particular in climate
sensitive regions. Decisions in sustainable water resources management require
scientifically sound information of the current water resources and fluxes and future
52
water availability.
The first objective of the work of S. Wagner is to provide estimations of the current water
resources and fluxes in a poorly gauged basin, the White Volta Basin in West Africa.
This is a central task to support water management authorities and stakeholders in
operational irrigation, water supply and running hydro-power strategies. To allow
investigations in ungauged or poorly gauged basins, these instruments and methods
should be applicable worldwide, cost-effective and preferably public domain. In poorly
gauged basins without automatic data recorders and online transmission other
meteorological data sources for near real time estimations of the terrestrial water
balance have to be used to overcome the temporal delay and/or the insufficient spatial
resolution. Therefore, a joint atmospheric-hydrological modeling system with MM5 and
WaSiM is developed which is able to provide near real time water balance estimations
within 48 h. Additionally to meteorological modeling results and observation data, a
TRMM product, which is available with approximately one month delay, is applied as
precipitation data source.
Figure 16: WaSiM setup: derived river network and boundaries of the White Volta Basin and its
subcatchments
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Besides meteorological driving data, land surface properties are essential input data for
distributed hydrological modeling. Land surface properties information is usually taken
from standard literature values and incorporated into hydrological modeling through
tables depending on the land use. The second objective of this work is to increase the
level of detail in the spatial and temporal dimension of land surface properties in
hydrological modeling using satellite derived land surface properties and to investigate
the impact on hydrological modeling results. In this study, products of the MODerate
resolution Imaging Spectroradiometer (MODIS) remote sensing system for albedo and
leaf area index LAI are imported into the hydrological model and investigated.
For sustainable decisions in water resources management, additionally to the modeling
result itself, the reliability or uncertainty of the result has to be quantified. Due to the fact
that the spatial variability of rainfall is often termed as the major source of error in
investigations of rainfall-runoff processes and modeling, the propagation of
uncertainties, resulting from the calculation of areal precipitation from point
measurements in water balance estimations, are investigated as third objective.
Therefore, different spatial interpolation methods, including external drift kriging, for
areal precipitation are applied, and their impact on water balance estimates is analyzed.
Furthermore, geostatistical simulations using the turning band method for areal
precipitation are performed in order to investigate the propagation of uncertainties in
water balance estimations. These results provide ranges of the temporal and spatial
distribution of water balance variables as consequence of uncertainties from the
calculation of areal precipitation from station data.
Figure 17: Coupling strategy for using atmospheric information in hydrological modeling
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With the key results a user-friendly model-based water balance system for
hydrometeorological decision support was developed. This system was transferred to
stakeholders in Ghana and Burkina Faso during two training workshops
“Hydrometeorological Decision Support for the Volta Basin” in Accra and Ouagadougou
in January 2008.
The main objective of this work is to provide estimations of the current water resources
and fluxes in a poorly gauged basin. This is a central task to support water management
authorities and stakeholders in operational irrigation, water supply and running hydro-
power strategies. In poorly gauged basins, where no automatic data recorders with
online transmission are available, other meteorological data sources for near real time
estimations of the terrestrial water balance have to be used to overcome the temporal
delay and/or the insufficient spatial resolution. Therefore, a model based, operational
water flow and balance system for the White Volta Basin is developed which provides
the required information. Near real time water balance estimations, which are available
with approximately 48 h delay, require the results of a meteorological model as input
data source. With the results of joint atmospheric-hydrological simulations, near real
time estimations of (i) atmospheric variables and (ii) the terrestrial water balance are
available.
Figure 18: Measured (Hydro Argos) water level [m] at Yarugu/Kaburi from 2004 until 2007
55
The results of the joint atmospheric-hydrological simulations in expost hindcasting mode
have shown that the meteorological model MM5 is able to provide the required
meteorological input data for near real time hydrological simulations in reasonable
quality.
Figure 19: Spatial distribution of simulated annual precipitation (MM5 Domain 3) for the Volta Basin for
2004 [mm]
Figure 20: of monthly averaged simulated vs. observed precipitation (MM5 simulation results are shown for
domain 2 and domain 3 - real time and scaled)
56
The performance of the MM5 simulations is good and comparable to the performance of
the scaled TRMM product 3B42, which is available with one month delay. The
hydrological model WaSiM is calibrated and validated with historical observation data.
The performance is good, considering the limited data availability of meteorological data
and the coarse resolution of soil and land use data.
Figure 21: Routed vs. measured (black) discharge [m3/s] for Nawuni for 2004 using (a) gridded, real time
(MM5 D2 and MM5 D3) or scaled (MM5 D2 sc and MM5 D3 sc) MM5 results, and (b) gridded, scaled TRMM
product 3B42 or station data
With the historical data sets, long-term (1961-2000) water balance simulations are
performed, which provide long-term information on the temporal and spatial distribution
of water balance variables in the White Volta Basin. The joint MM5-WaSiM results for
57
near real time estimations in expost hindcast mode show a good performance for 2004
and a weaker one for 2005 due to overestimation of precipitation. Scaled MM5 results
improve the simulation results considerably for 2005. The performance of hydrological
simulations driven by TRMM data is lower compared to the simulations with real time
and scaled MM5 output. In general, the performance comparison of hydrological
modeling results using different meteorological data sources shows, that the estimation
and representation of the high spatial and temporal distribution of precipitation is crucial
for the hydrological simulation results.
For an increased level of detail in the spatial and temporal dimension of land surface
properties in hydrological modeling, satellite derived land surface properties are
imported into the hydrological model. In this study, the MODIS products for albedo and
leaf area index LAI are used.
Figure 22: Seasonal cycle of monthly mean precipitation [mm/month], leaf area index LAI (red) and surface
albedo (green) averaged over the White Volta Basin for 2004
Both variables have an impact on potential evapotranspiration which is calculated with
the Penman-Monteith approach. The comparison between static tabulated values from
standard literature and dynamic MODIS estimates shows for albedo a comparable
spatial distribution with an increased level of detail in the spatial dimension for the White
Volta Basin. For the LAI, the temporal development is not sufficiently represented by two
seasons with the static tabulated approach in the classic hydrological model setup. In
comparison to MODIS LAI, the tabulated values overestimate the LAI during the dry
season and underestimate it during the rainy season in the southern part of the
58
catchment. The assimilation of dynamic MODIS estimates of albedo and LAI in
hydrological modeling shows a minor impact on daily time series of water balance
variables. However, the sum curves of daily differences identify for potential
evapotranspiration slightly higher values during the complete year using MODIS
estimates for albedo. The use of MODIS estimates for LAI leads to lower potential
evapotranspiration values during the dry and equal to slightly higher ones during the
rainy season, which agrees well with the differences of albedo and LAI grids using static
tabulated or dynamic MODIS values. The impact of dynamic MODIS estimates of albedo
and LAI on the spatial distribution of water balance variables in the White Volta Basin is
very heterogeneous in space with positive and negative signs in almost all
subcatchments. In total, the percentage change of mean annual sums using dynamic
MODIS estimates compared to static tabulated values amounts to plus 2% for potential
and plus 1% for actual evapotranspiration and minus 1% for total runoff for 2004.
Furthermore, the use of dynamic MODIS estimates decreases standard deviation values
of evapotranspiration and total runoff on subcatchment and catchment scale compared
to tabulated static ones for albedo and LAI.
Figure 23: Annual potential evapotranspiration [mm] for the White Volta Basin for 2004 using (a) static
tabulated values for albedo and LAI, and (b) dynamic MODIS estimates for albedo and LAI
59
For the propagation of uncertainties, resulting from the calculation of areal precipitation
from point measurements, in water balance estimations the following is investigated.
First, different spatial interpolation methods for areal precipitation are applied and their
impact on water balance estimates are analyzed. Additionally to the standard
interpolation methods inverse distance weighting and Thiessen polygons, ordinary and
external drift kriging are applied for the spatial interpolation. The areal annual
precipitation fields show that the application of external drifts support the spatial
interpolation of point measurements. The long-term mean precipitation field provides, in
particular in regions with extremely coarse observation networks, important additional
information for the spatial interpolation of station data. The performance comparison
with cross validation results shows that kriging methods outperform the standard
interpolation ones. Thereby, the use of external drifts increases the variance of the areal
precipitation fields. The impact of the selected spatial interpolation method for areal
precipitation on the temporal and spatial distribution of water balance variables is minor
for spatially aggregated variables and the corresponding time series. However, the
selected interpolation method affects the spatial distribution of water balance variables.
Although the differences are very heterogeneous in space, the impact of the applied
external drift is clearly visible.
Second, geostatistical simulations for areal precipitation are performed for the
investigation of propagation of uncertainties in water balance estimations. Turning band
simulations increase the spatial variability of the precipitation fields, which leads to an
increase of spatial variability for actual evapotranspiration and a decrease of variability
for total discharge, which is in good agreement with the kriging results.
60
Figure 24: Results of hydrological simulations using “Turning Bands” simulated precipitation fields for 2004:
(a) Spatial distribution of standard deviation of total discharge [mm], and (b) time series of daily range (grey)
and mean value (black) for precipitation (top), and routed vs. measured (red) discharge (bottom) for Nawuni
61
For sustainable decisions in water resources management, the entirety of all
hydrological simulation results, driven by equally probable precipitation fields from the
turning band simulations, provides ranges of the temporal and spatial distribution of
water balance variables. These ranges are the consequence of uncertainties from the
calculation of areal precipitation from station data. The propagation of uncertainties from
the areal estimation of precipitation in the spatial and temporal distribution of water
balance variables is clearly visible. The partly large range of possible daily precipitation
amounts leads to a wide range of possible realizations in particular for the total runoff
time series. The comparison of turning band results for routed discharge shows that the
width of possible realizations varies considerably depending on the location of the
subcatchment and the uncertainties of the upstream subcatchments.
Altogether it was shown that the integration of atmospheric modeling and satellite
derived land surface data provides a significant benefit for hydrological modeling,
especially in regions with weak infrastructure and coarse-resolution observation
networks. The prerequisite of worldwide available data sources and public domain
models allows a transfer of the methodological approach of a model based water
balance monitoring system to other basins and regions in the world.
The PhD study of P. Laux focused on two research topics: (a) Analysis of important
precipitation feature in the Volta Basin on daily scale, (b) Application and evaluation of
the ORS algorithm for Cameroon. The combination of a conventional Markov chain
model (zero and first order) and a gamma distribution model are found to be applicable
to derive meaningful agricultural features from precipitation in the Volta Basin (West
Africa). Since the analysis of the monthly or annual precipitation amount does not
provide any adequate information on rainfall timing and sufficiency of crop water
requirement, rainfall modeling was performed on a daily time scale for 29 rainfall
stations. The modeled rainfall features follow distinct spatial patterns, which will be
presented as maps of i) rainfall occurrence probabilities, and ii) recommendations of
optimal planting dates following an algorithm of Laux et al. (2008) to estimate the
agriculturally relevant onset of the rainy season (ORS). In addition, the Effective Drought
Index (EDI) working on daily time scales is calculated in order to assess drought
properties of 5 different rainfall regions within the Volta Basin. Apart from the common
way of separately modeling the duration and intensity due to their different distributions,
a copula approach is chosen in this study to construct a bivariate drought distribution.
62
The ORS algorithm (Laux et al., 2008), which is calculating the planting date for each
year, is coupled to the physically based crop model CropSyst to estimate agricultural
productivity. This study is conducted for Cameroon due to the following reasons:
i) lack of data for crop modeling in the Volta Basin, and,
ii) in order to evaluate the ORS algorithm, developed for the Volta Basin, for a
different tropical semi-arid region.
A Monte Carlo approach is applied to generate annual planting dates (1979-2003).
Therefore, the definition constraints, which are allowed to vary within reasonable
parameter ranges, are generated randomly. The averaged crop yield is serving as
performance measure for each realization. The parameter range of the best realizations
is retained. Various iterations are necessary to obtain a robust set of definition
parameters. The coupled ORS definition-crop modeling system is applied for different
crop species and observation sites across Cameroon for the period 1979-2003. It is
shown that the derived optimal planting dates would allow significantly increased crop
yields compared to the existing planting rules. Finally, based on the robust definition
parameterizations, expected future crop yield is derived using statistically downscaled
GCM scenarios.
Analysis of important precipitation feature in the Volta Basin on daily time scale
Figure 25 exhibits the observed and fitted dry spell occurrence probabilities within the
following 30 days calculated for each DOY at Bole.
Figure 25: Observed (*) and fitted (-) dry spell occurrence probability within the following 30 days for each
day of the year at Bole, based on rainfall data from 1961 to 1999
0 50 100 150 200 250 300 350 4000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
63
The probability decreases below 10% around DOY 160 (08 June). After this, the
probability of dry spells increases to more than 60% (around 12 August). Then, it
decreases again to less than 40% (25 September), and finally, it increases again rapidly.
Assuming e.g. a probability threshold value of P = 0.2, which is not allowed to be
exceeded at planting time, the time window for planting is restricted to the period from
approximately DOY 120 to DOY 180. These probabilities were calculated for all stations
in the Volta Basin, and
Figure 26 illustrates the spatial distribution of the dates with minimum dry spell
occurrence probabilities.
Figure 26: Date with minimum dry spell occurrence probability for the following 30 days, representing the
optimal planting date [Day of Year]. External drift kriging, including distance-to-sea information, was applied
for spatial interpolation
64
The pattern approximately reflects a north-south distribution following the movement of
the ITCZ. The respective probabilities of these dates are presented in Figure 27.
Figure 27: Probability of the dry spell occurrence within the following 30 days [%]. External drift kriging,
including distance-to-sea information, was applied for spatial interpolation
The minimum dry spell probabilities hold a regional maximum in the northwest of Ghana
and southwest of Burkina Faso (~30 %). This is of crucial importance to farming
management. In these regions, dry spells are more likely to occur within the following 30
days and, thus, crop failure is more likely to occur. Focused irrigation strategies
especially in regions with a very high dry spell probability would be beneficial to enhance
food security.
65
To derive meaningful agricultural drought properties across the Volta Basin, a regional
scale is chosen. To facilitate the modeling, the Volta Basin is divided into 5 sub-regions
(Figure 28). Further details of the applied regionalization strategy can be found in Laux
et al. (2007, 2008). As drought duration and drought intensity offer a significant
dependence structure, a bivariate distribution is used to model the drought duration and
intensity jointly. A copula approach is used to separate the bivariate dependence
structure from their respective uniform marginal distributions.
Two cases of bivariate drought periods can be defined by either „drought duration and
drought intensity‟ exceeding a specific value ( - case) or by „drought duration or
drought intensity‟ exceeding a specific value ( - case).
Figure 28: Location of the Volta Basin and spatial distribution of areas with similar rainfall characteristics,
represented by five ellipses (right), (source: Laux et al., 2007).
Figure 29 displays exemplarily the isolines of bivariate drought duration and drought
intensity return periods TDS for the - case in the southernmost region A (top) and the
northernmost region E of the Volta Basin (bottom) using the effective drought index
(EDI) values. In both regions, 1 larger than one-in-1000-year drought occurred. For
region A, 3 larger than one-in-100-year droughts and 1 larger than one-in-10-year
droughts occurred, whereas in region E, no larger than one-in-100-year drought, but 4
one-in-10-year droughts happened.
66
0 200 400 600 800 1000 1200 14000
200
400
600
800
1000
1200
1400
1600
10yr
100yr
1000yr
Drought duration [days]
Dro
ug
ht
inte
nsit
y [
cu
m.
ED
I]
Figure 29: Isolines of bivariate drought duration and drought intensity return periods TDS for the - case in
region A (top) and region E (bottom) using 10-day moving-averaged EDI values. The dots represent the single
drought events. The location of the regions within the Volta Basin is shown in Laux et al. (2009)
Application and evaluation of the ORS algorithm for Cameroon
Figure 30 shows an example of the interannual differences in the simulated crop yield
using the calculated planting dates (ORS definition) and the traditional planting date.
Except for one (four) year(s), the crop yield could be increased significantly for maize
(groundnut) following the ORS definition of Laux et al. (2008). The mean value (standard
deviation) of calculated planting date at Garoua is DOY 214 (29 days) for maize and
0 500 1000 15000
200
400
600
800
1000
1200
1400
1600
10yr
100yr
1000yr
Drought duration [days]
Dro
ug
ht
inte
nsit
y [
cu
m.
ED
I]
67
DOY 180 (29 days) for groundnut. The traditional planting date at Garoua is DOY 135.8
Compared to the traditional planting rules, using the ORS definition based planting dates
could increase the mean attainable crop yields by up to 22.4% for maize and 7.8% at
Garoua for groundnut. Higher increases of crop yield, in general, could be achieved in
anomalously wet years. Similar increases of mean attainable crop yields using the ORS
definition are found for the other observation stations (results not shown).
1980 1985 1990 1995 2000-1
0
1
2 Maize
Groundnut
(M
CY
OR
S -
MC
Ytr
ad
)
(t/h
a)
Year
-2
-1
0
1
2
Pre
cip
ita
tio
n
an
om
aly
Figure 30: Precipitation anomaly (top) and difference between simulated mean crop yield (MCY) using the
ORS definition and simulated MCY using the traditional planting date (15 May, DOY 135) for maize and
groundnut (bottom) at Garoua (Cameroon)
2.2.2 Sub-project S2: Hydro-meterological Observatory
The Biophysical Observation Network (BON) within the framework to the GLOWA-Volta
project was maintained and extended. The prospected new research site in northeastern
Ghana was investigated, and a field site evaluation carried out.
Milestones achieved:
Completed assessment of coverage requirements (needs for selective
8 Ndemah, R. (1999). Towards an integrated crop management strategy for the African stalk borer, /Busseola fusca/
(Fuller) (Lepidoptera: Noctuidae) in maize systems in Cameroon. Doctoral thesis.
68
expansion) in existing data collection networks; identification of highest-priority
expansion sites
Enduring protocols for site maintenance and data retrieval at joint GVP/HSD/MSD
Services meteorological monitoring sites established
Complete development of the public website and data portal (through sub-
projects I2, I3)
Milestones achieved with deviations:
Complete automated archiving and quality control procedures on GVP server:
Archiving procedures are still being done manually since data quality assessment
and quality control needs thorough investigation of all possible data errors and
flaws. Protocols for standardized control and correction of data are already in
place, but verification of these protocols requires manual data processing to see if
all possible errors are being taken into account. The necessary macros for the
automated data archiving have been developed and implemented.
Methodology and Research Results:
The Biophysical Observation Network (BON) was setup within the framework of the
GLOWA Volta Project (GVP) and the BIOTA West project by J. Szarzynski, U. Falk and
J. Hendrickx. Within Phase III of the GVP, the BON was maintained and extended with
new sites, sensors calibrated and existing sites improved. Data post-processing and
analysis of the assembled data sets are being automated and the data sets introduced
into the Geodata portal. Synoptical data sets collected from the Meteorological Services
of the riparian countries in the Volta Basin are being analyzed for quality criteria and
control. In the following is a detailed list of research activities:
Revision and data acquisition of the micrometeorological research sites in
Boudtenga, Dano, Fada N‟Gourma and in Bontioli Park (Burkina Faso) as well as
in Pendjari Park (Benin). Climatological sensors were replaced in regular intervals
when aging process affected the accuracy of the equipment and the quality of the
measurements.
Setup of a new research site in Ouahigouya (Sahelian climate zone) in the north
of Burkina Faso in March 2008.
The climate station in Dano was taken down in November 2007; due to regular
vandalism, the safety of the station was not granted anymore.
69
Revision of the climate stations in Ghana showed that most of the equipment was
worn out, in a desolate state and the sensors in great parts deteriorated. New
calibration of the sensors was not possible due to eroded sensor cabling right into
the sensors. The stations in Ejura and Tamale were taken down in January 2007,
and the GVP climate station in Navrongo left for the local researchers to take
down.
Modification and expansion of the precipitation measurement network in Pendjari
Park (Benin). As a contribution to cooperation with the BIOTA counterparts in
Benin, a network of Hobo stations was setup and maintained in the Pendjari
National Park throughout the third phase. Due to vandalism, several of the
stations needed repair in regular intervals.
Coordination talks with counterparts (INERA, Meteorological Services etc) were
carried out when staying in Burkina Faso, Ghana and in Pendjari Park (Benin)
The scintillometry site at Boudtenga had suffered severe damage due to a hail
storm in 2007, and was re-adjusted and measurements continued. Maintenance
and data acquisition was revised.
Investigation of a possible new hydrological research site in North-Eastern
Ghana, the Atankwidi catchment, was carried out and possible locations for
climate stations and scintillometers as well as eddy-covariance stations identified
and GPS coordinates taken.
The Eddy Covariance sites in the Bontioli National Park and at the Boudtenga
research site in Burkina Faso were reinstalled and improved. Regular overflight
missions to map land-surface properties with a camera system purchased within
the BIOTA West project are being carried out.
The assembled biophysical data base allows for extensive comparison between
different measurement techniques and validation of remote sensing products for
land surface properties. The data base provides a basis for cross-scale analysis
of exchange processes between atmosphere and land-surface/vegetation cover
on the basis of observation, modeling and remote sensing.
Participation in the AMMA workshop “Workshop on impacts of climate fluctuations
and trends in West-Africa”, 26 February to 02 March 2007 in Bamako, Mali, for
the development of cooperations with AMMA partners and the EU project
ENSEMBLES.
Cooperations with the EU project CarboAfrica and the BMZ funded project
ALUCCSA were initiated and relations strengthened by associating the eddy-
covariance sites with the CarboAfrica project.
70
Capacity building was carried out through doctoral and master students, i.e. Tia
Lazare (Ivory Coast) and Gildas Boko (2iE master student, Burkina Faso).
For capacity building in the research region, a workshop was given in cooperation
with Prof. Jan Hendrickx (New Mexico Tech, USA) at the UNU in Accra Ghana
21-24 January 2009, about Estimation of Evapotranspiration using remote
sensing imagery: “SEBAL/METRIC Workshop for ET Estimation using Landsat
Images”
Within the framework of several field campaigns, new micrometeorological and
climatological stations were installed in the main investigation region of Burkina Faso.
The exact locations of sites were chosen in accordance with representativeness and
overall research questions of GVP, to achieve the maximum of synergetic effects with
other GVP topics. The climatic data are part of direct monitoring of abiotic parameters
and ongoing research. Alongside with the field data from the project owned research
sites, data of national meteo services in West-Africa as well as of international
organizations as IRD and FAO were collected and brought together in a joint data base.
Based on time series analysis and geostatistical interpolation, georeferenced maps of
different climatic variables were compiled.
Further experimental field work was carried out in Burkina Faso and Benin. In Pendjari
National Park, Benin, a network of stations measuring precipitation, temperature and
humidity was set up, to gain insight into the small-scale variability of meteorological
surface boundary layer conditions. Measures for capacity building took place by
providing individual training in the subject of applied biophysical and
micrometeorological measuring approaches. A camera system for the overflight
missions to map land surface properties was purchased and first setup in Bonn. The
technician from Burkina Faso, Mr. Gildas Boko, was invited to Bonn, Germany, where
he received a training course on the operation, data processing and analysis during an
internship at ZEF that was part of his education at 2iE, International School for
Engineers of Water and Environment, in Ouagadougou. Instruction and testing as well
as the organization of infrastructure in Burkina Faso was set in place to prepare airborne
mapping of land surface properties that are being carried out at the end of both the dry
and the rainy season. Biophysical measurements that were achieved during the duration
of the GVP project phases, were compiled and used to parameterize models (e.g.
SVAT, SEBAL/METRIC etc) to characterize and estimate the representative ecosystem
and landscape processes.
71
Application and use of project results
Within the GVP network a basic cooperation to all subprojects was established partially
due to the service function of the climatological sub-project. Outside of GVP,
cooperation with the BIOTA West project was intensified and the climatological and
biophysical measurements consolidated to a network at the Center for Research
Development at the University of Bonn. Cooperation with the EU framework program
CarboAfrica were set-up and possible synergies localized. Further points of contact
evolved through the formation of a Virtual Institute, based on the collaboration between
the University of Bonn and the Helmholtz Society. Aim of this constitution is the
investigation of horizontal and vertical fluxes of matter in natural savannas that was
carried out by ZEF and the Institute of Meteorology and Climate Research (IFU/IMK) in
Garmisch Partenkirchen. The micrometeorological measurements by GVP have
contributed within this context to the registration of vertical fluxes of energy and water. A
major part of the investigations were carried out in the Bontioli National Park (BNP) in
the Dano Region, in western Burkina Faso. A similar research site at was set up in
Boudtenga, an agricultural site near Ouagadougou, Burkina Faso. In addition to the
natural open savanna research site in the BNP, human impact on biophysical processes
can be investigated here. GVP and BIOTA subprojects have the main goal to improve
accessibility and use of water and natural resources for the local population.
Automation of the BON and remote access to the different stations will increase the
value of this network to national and transnational hydrometeorological services, and will
make high precision meteorological data available to political decision makers. This is
underway and test routes are in place. Currently in process is the work on validation of
remote sensing products by ground truth data measured by climatological and
micrometeorological measurements, as well as airborne data. Results from models
working on different scales (plant, ecosystem, landscape) need to be extrapolated and
refined to match the scales of ground measurements that have variable probing areas
as well as satellite imagery that have fixed probing areas. A detailed analysis of the
different footprints of measurements is necessary to proceed with the intercomparison.
In order to transfer the Biophysical Observation Network to the respective authority,
training courses on the operation and maintenance of the climatological and biophysical
stations are planned with the Meteorological Services, project partners, and the
transregional institution Volta Basin Authority (VBA). The VBA was set in place in the
past three years to handle transregional strategies that are related to water.
72
Data availability and management
The climate database set up within the first phase was extended with the data sets of
the Biophysical Observation Network (BON) and data sets of the Institut de Recherche
pour le Développement (IRD), the World Meteorological Organisation (WMO) and the
Agrometeorology Group, Food and Agriculture Organization (FAO) of the United
Nations. Synoptical Observations of the Meteorological Services of the countries in the
research area were also added after data screening for quality assessment and control.
Data mining
In the context of the meteorological ground measurements, registration and estimation
of solar and terrestrial radiative and energy flux components are of substantial
importance. The acquired parameters are also used as ground truth data for evaluation
of remote sensing products, for instance at the experimental sites Boudtenga and
Bontioli.
First results of the validation of LandSAF products (Land Surface Analysis Satellite
Applications Facility (LSA SAF)) on the basis of MSG data (Meteosat Second
Generation) and ground truth data from Burkina Faso as well as flux estimations of CO2,
water vapor and energy in Bontioli National Park (Burkina Faso) and above a
agricultural site in Boudtenga (Burkina Faso) were presented at two past annual
meetings of the European Geosciences Union (EGU) and at the meeting of American
Geosciences Union (AGU) in 2007, and at the International Symposium of Remote
Sensing and Environment (ISRSE) in 2009.
Extension of internal and external cooperation
Within the report period, the cooperation with project- and external partners was
extended. The collaboration with counterparts in Burkina Faso - Institut de l‟Environment
et de Recherche Agricoles (INERA) and the national Meteorological Service - and Benin
- Centre National de Gestion des Réserves de Faune (CENAGREF) were intensified.
Cooperations with other major projects like CarboAfrica and other universities working in
West-Africa, e.g. Univ. of Denmark, were established and strengthened.
Capacity building
Besides the local field assistants, several members of the Meteorological Service were
trained in maintenance and supervision of the installed micrometeorological station
network. Moreover, members of the Pendjari National Park Managements were
instructed in maintenance and operation of supplemental measurement modules. Our
technician G. Boko now attends to all stations along the East-West axis of the
73
monitoring network and guarantees for continuous data acquisition, but also uses the
assembled data base for achieving his Masters degree at 2iE, the International School
for Water in Ouagadougou (Burkina Faso). He is also involved in building technical and
analytical capacities in the Meteorological Services at national level, to hand over the
BON stations after the end of the projects.
The research of R. Kasei on the determination of sensible heat flux using Large
Aperture Scintillometers was finished and accepted by the University of Cape Coast at
the beginning of this Phase. He started to work in the new area of models of probability
and risk applied to water resources management in the Volta Basin under climate
change in October 2006. Within the last two and a half years, he has been applying the
model WaSiM to the Volta Basin with the goal of understanding the hydrology of the
watershed of the Volta and to assess the impact of model climate scenarios to water
resources and the risk to the rising population posed by the changes.
This period covered most part of his PhD work. In order to obtain the data for his
analysis, he spent six month in the catchment mainly Ghana and Burkina Faso,
collecting and gathering data for temperature, precipitation, wind speed, global radiation,
stream flow, and soil moisture. Existing data mainly from the national institution were
verified and cleaned of unreliable recordings. Data collected for the meteorological
parameters are mainly from 1961 to 2004 and for the hydrological parameters, from
1958 to 2006 with gaps.
The hydrological model (WaSiM-ETH) is parameterized and fine tuned to represent the
hydrological processes of the Volta Basin. The calibration period extended over 5 years
before 1970.
Main results of his work are:
Preliminary hydrological outputs from WaSiM-ETH for some catchments in the
Volta Basin.
Working Model for the meteorological part of the WaSiM model
Soil map for the basin from FAO 1996 for WaSiM inputs
Evaporation maps
Rainfall distribution maps.
74
2.2.3 Sub-project S3: Remote Sensing and Surface Energy Flux
This sub-project deals with the further development and validation of remote sensing
algorithms for estimation of the latent heat flux, i.e. evapotranspiration, in the Volta
Basin. This sub-project dovetailed with parallel research projects of Prof. Hendrickx in
New Mexico, Wyoming, Panama, Colombia, and Suriname. Scintillometer technology
developed in the Volta Basin is used in the USA and Latin America, while algorithms
developed and tested in the USA are used in the Volta Basin.
Milestones achieved
Compare ET maps derived from Landsat images at high resolution with ET maps
downscaled from MODIS images.
Implementation of downscaling procedures for preparation for high resolution ET
maps.
Milestones achieved with deviations
A series of pilot maps at a resolution of 100 m or less that provide ET information
during one hydrologic year in the Upper East Province using SEBAL and the
Schüttemeyer method.
One evapotranspiration map with 30 m resolution has been prepared for Northern
Ghana. Other maps have not been prepared for lack of a designated watershed
with high quality ground measurements and hydrologic model simulation results.
First the Upper East Region was selected, then the Atankwidi watershed; in the
end the Boudtenga site was selected using high quality data from 2009.
Implementation of SEBAL in Ghana using the SEBAL code in Matlab.
A SEBAL code in ERDAS Imagine has been implemented in Ghana and Burkina
Faso and is now used in ZEF by Dr. Falk and her research group. In addition, Dr.
Hendrickx and Dr. Falk have taught a SEBAL/METRIC workshop in Accra in
January 2009 with more than thirty participants from Ghana and Burkina Faso.
Milestones not achieved
Installation of mobile MSG receiving station and storage system
Just prior to our installation, Meteosat provided African countries with MSG
receiving stations.
Automatic implementation of SEBAL using scintillometer measurements.
As explained in the section “Methodology and Research Results” an inter-
comparison of scintillometers revealed instrument errors among scintillometers as
75
large as 23%. Therefore, scintillometers are not yet ready to be used for ground
truth measurement of sensible heat fluxes for adjusting ET remote sensing
algorithms.
Integration of SEBAL and the Schüttemeyer method into a procedure for the
derivation of a continuous ET product for the Volta Basin.
Due to the lack of a designated experimental watershed this activity was never
implemented since it depends on a number of different disciplines that all work together
in one focal watershed. The preparation of twelve ET maps for a watershed without the
support of high quality ground measurements and advanced simulation results would
have been a wasted effort.
Methodology and Research Results
The major issue addressed by this sub-project was “how to prepare reliable ET maps
under conditions of partial and complete cloudiness” using and further developing
existing operational remote sensing algorithms such as the Surface Energy Balance
Algorithms for Land (SEBAL)9 and “Mapping Evapotranspiration at High Resolution and
with Internal Calibration (METRIC)” 10 that had been developed and validated for clear
sky conditions. Cloud algorithms are needed because large parts of the southern Volta
Basin as well as other research areas of Dr. Hendrickx in Wyoming, Panama, Colombia,
and Suriname are often entirely or partially covered by clouds when the Landsat and
MODIS satellites capture their optical images. The probability of acquiring a high quality
Landsat or MODIS image with few clouds varies from high in the region north of
Ouagadougou to very low in the region between Accra and Ouagadougou. As a result it
is impossible to acquire a sufficient number of high quality clear sky satellite images that
are needed for monthly, seasonal, and annual ET evaluations over the entire Volta
Basin.
9 Bastiaanssen, W.G.M., M. Menenti, et al. (1998). A remote sensing surface energy balance algorithm for land
(SEBAL): 1. Formulation. J. of Hydrology 212-213:198-212.
Bastiaanssen, W.G.M., E.J.M. Noordman, et al. (2005). SEBAL model with remotely sensed data to improve water-
resources management under actual field conditions. J. Irrig. and Drain. Engrg., ASCE 131:85-93.
10 Allen, R.G., M. Tasumi, et al. (2007). Satellite-based energy balance for mapping evapotranspiration with
internalized calibration (METRIC) - Model. Journal of Irrigation and Drainage Engineering 133:380-394.
76
Implementation of SEBAL/METRIC approach for ET Mapping using Landsat and MODIS
Images
For a reliable estimate of ET over the Volta Basin, ET maps with the spatial resolution of
Landsat images, i.e. 30 m for visual bands to 120 m for thermal band, are desirable due
to the small size of most agricultural fields. Unfortunately, Landsat images are only
captured once every 16 days and in the southern part of the basin have a high likelihood
to be degraded by clouds. One way to deal with the effect of cloudiness on the
availability of Landsat images is to use MODIS images instead. A MODIS image with a
sensor view angle less than about 20 degree is available every four days so that the
likelihood of acquiring a cloud free MODIS image is rather high. However, the spatial
resolution of MODIS images varies from 250 m for the visual bands to 1000 m for the
thermal bands which is too coarse for monitoring field scale changes. Therefore, one
objective of this sub-project was to develop procedures to downscale ET maps prepared
from MODIS images to ET maps with the high resolution of Landsat images.
Figure 31: Map of the Volta Basin with the principal rivers. The dotted lines represent the study area
covering a large part of the White Volta Basin; the black lines correspond to the Land Use/Land Cover
(LULC) map around Navrongo.
77
First, SEBAL was implemented for the preparation of ET or latent heat flux, sensible
heat flux, and soil moisture maps at the end of the rainy season (October 30, 2002)
using two Landsat images joined together (Path 194, Rows 52 and 53) and at the end of
the dry season (March 7, 2003) for the southern image (Path 194, Row 53) (Compaoré
et al., 2008; Hendrickx et al., 2006). Figure 31 shows the location of the maps in the
Volta Basin while Figure 32 and Figure 33 present the maps at the end of, respectively,
the rainy and the dry season. Figure 32 nicely demonstrates the increasing ET and soil
moisture moving from the north to the south in the basin while the sensible heat flux is
decreasing. Figure 33 shows that at the end of the dry season ET only occurs along the
rivers and on irrigated fields; in the dry land areas vegetative production has come to a
halt with the exception of some trees in the savanna. However, the ET of these trees is
too small in comparison to a 30x30 m pixel to be detected on the ET map of Figure 33.
A qualitative validation of the ET maps was conducted by calculating the average ET for
each Land Use/Land Cover (LULC) class at the start and the end of the dry season
(Table 1). The ranking of average ET‟s and the crop coefficients for each LULC class
are as expected and, therefore, confirm the quality of the SEBAL derived ET maps from
Landsat images in the Volta Basin.
Figure 32: Maps of ET, sensible heat flux, and soil moisture (degree of saturation) at the end of the rainy
season (October 30, 2002) derived from Landsat image. The scale of these maps is different from Figure 33
since these maps cover two Landsat images. The area of Figure 33 is the lower half of this figure.
78
Figure 33: Maps of ET, sensible heat flux, and soil moisture (degree of saturation) at the end of the dry season
(March 7, 2003) derived from Landsat image (Path 194, Row 53). The scale of these maps is different from
Figure 32 since these maps cover the lower half of Figure 32. There is some contamination by clouds in the
upper NW corner of the image.
Table 1: Distribution of evaporation and crop coefficient (Kc) by LULC class at start (30 October, 2002) and
end (March 7, 2003) of the dry season, in the Navrongo area, Ghana.
79
Since clouds interfere too often with the quality of Landsat images in the southern parts
of the Volta Basin, SEBAL was also evaluated on the MODIS images of October 30,
2002, (Figure 34) and March 7, 2003. Visual comparison between ET maps derived
from Landsat and MODIS images showed very good agreement as did the comparison
of the histograms of the daily evapotranspiration rates (Figure 35) (Compaoré et al.,
2008; Hendrickx et al., 2006). Figure 36 compares the Landsat and MODIS ET maps in
the area around Tono dam. Thus, MODIS derived ET maps are a viable option for the
monitoring of ET in the Volta Basin as well as in New Mexico, Wyoming, Panama,
Colombia, and Suriname. On the basis of these promising results up- and down-scaling
procedures between Landsat and MODIS images were developed and tested on high
quality cloud free images from New Mexico (Figure 37).
Figure 34: MODIS and Landsat images at the end of the rainy season. The Landsat image is composed of two
images (Path 194, Rows 52 and 53). At the end of the dry season (March 7, 2003) only the southern image was
used (Path 194, Row 53).
80
Figure 35: Evaporation histograms of Landsat and MODIS evaporation maps on March 7, 2003.
Figure 36: MODIS and Landsat maps of evaporation at the end of the dry season (March 7, 2003) in a 22 by
21 km area around Tono dam. Highest evaporation rate (>7 mm/day) is black, zero evaporation is white.
81
Figure 37: Landsat and MODIS images covering the Middle Rio Grande Valley in New Mexico, USA. The
Landsat and MODIS images have different temporal and spatial resolutions.
Four different up-scaling procedures were evaluated and it turned out that output up-
scaling with simple averaging performs best (Figure 38). Two down-scaling procedures
were evaluated: input down-scaling and output down-scaling. In each down-scaling
scheme, disaggregated imagery was obtained by two different processes: subtraction
and regression. The primary goal was to investigate the effect of the different down-
scaling schemes on the spatial distribution of SEBAL derived ET. All four proposed
down-scaling methodologies can generate reasonable spatial patterns of the
disaggregated ET map but output down-scaling with regression between images is the
most preferred scheme since it does not depend on exact geo-referencing between the
Landsat and the MODIS images (Figure 39).
These good results for ET mapping with the SEBAL and METRIC algorithms at Landsat
and MODIS scale have motivated the transfer of these techniques to Dr. Ulrike Falk in
ZEF and to more than 30 participants in a SEBAL/METRIC Workshop organized in
Accra in January 2009.
82
Automatic Implementation of SEBAL/METRIC approach for ET Mapping using
Scintillometer Measurements
The long term goal for the Volta Basin is an automatic implementation of the
SEBAL/METRIC approach for continuous ET mapping based on remote imagery of
MODIS, Meteosat, and/or GOES platforms in combination with high quality ground
measurements along a representative scintillometer transect. Using ground
measurements of incoming and outgoing short and long-wave radiation, reference
evapotranspiration, and sensible heat flux measurements at the pixel scale with
scintillometers as well as remote estimates at the pixel scale by SEBAL/METRIC of the
net radiation, soil heat flux, and sensible and latent heat fluxes it is expected to obtain in
the future reliable ET estimates needed for improved water resources management. The
proposed milestones for this ambitious objective were based on two expectations: (1)
the availability of high quality ground measurements of the energy balance components
in the proposed experimental watershed and (2) accurate sensible heat flux
measurements by scintillometers. One setback for the sub-project was that the
proposed experimental watershed never was installed in the field so that high quality
ground measurements have not been obtained until the upgrade of the Boudtenga
scintillometer site in the final phase of the project. However, the most serious setback for
the sub-project as well as for Dr. Hendrickx‟s research projects in New Mexico,
Wyoming, Panama, Colombia, and Suriname was the detection of a large inter-
instrument error among Kipp&Zonen scintillometers in New Mexico in 2008.11
11 Kleissl, J., S.-h. Hong, and J.M.H. Hendrickx (2009). New Mexico scintillometer network. Supporting remote
sensing and hydrologic and meteorological models. Bulletin American Meteorological Society 90:207-218
Kleissl, J., J. Gomez, et al. (2008). Large aperture scintillometer intercomparison study. Boundary Layer Meteorol.
128:133–150
83
Figure 38: ET maps from output up-scaling using simple averaging resampling on June 16, 2002. Spatial
resolutions are 60, 120, 250, 500 and 1000 m from the left. This method produces the most statistically and
spatially predictable behavior (Hong et al., 2009a).
Figure 39: Down-scaled ET map from four different down-scaling procedures (1) output with subtraction, (2)
output with regression, (3) input with subtraction and (4) input with regression. Output with regression is the
preferred procedure. Enlarged areas (6 x 9 km2) shown at the bottom correspond to the dotted square of the
upper images (Hong et al., 2009b).
84
Two field studies with six large aperture scintillometers (LASs) were performed in New
Mexico using horizontal and slant paths between the receiver and transmitter of each
scintillometer. The accuracy of this novel and increasingly popular technique for
measuring sensible heat fluxes was quantified by comparing measurements from
different instruments over nearly identical transects. Random errors in LAS
measurements were small, since correlation coefficients between adjacent
measurements were greater than 0.995. However, for an ideal set-up differences in
linear regression slopes of up to 21% were observed with typical inter-instrument
differences of 6%. Differences of 10% are typical in more realistic measurement
scenarios over homogeneous natural vegetation and different transect heights and
locations. Inaccuracies in the optics, which affect the effective aperture diameter, are the
most likely explanation for the observed differences (Figure 40)12. The largest difference
between two scintillometers along a slanted path was about 40%. Such large differences
exceed the typical inaccuracy for the SEBAL/METRIC approach which is about 15% for
a daily ET and about 5% for annual or seasonal ET estimates.9
During the international scintillometry workshop in New Mexico in the fall of 2009, a
similar difference was measured between two new Kipp&Zonen scintillometers and also
the new Scintec scintillometers were not without deviations. Both companies,
Kipp&Zonen as well as Scintec are working hard to improve the performance of their
scintillometers and better products are expected in the near future. Nevertheless, for the
moment scintillometer measurements such as those obtained in Boudtenga (Figure 41)
cannot be used for calibration or validation of the remote sensing algorithms SEBAL and
METRIC due to these rather large inter-instruments errors.
Currently, Dr. Hendrickx and Dr. Falk are investigating whether scintillometers can be
calibrated against sensible heat flux measurements with eddy covariance along a
transect in New Mexico. If calibration is possible, the scintillometers can be employed for
sensible heat flux measurements at the pixel scale; if not, we have to wait for improved
scintillometers.
12 Kleissl J, C.J. Watts et al. (2009). “Scintillometer Intercomparison Study-Continued.” BOUNDARY-LAYER
METEOROLOGY 130(3): 437-443
Kleissl J, J. Gomez et al. (2008). “Large aperture scintillometer intercomparison study.” BOUNDARY-LAYER
METEOROLOGY 128 (1): 133-150
85
Figure 40: Scatter plots of sensible heat flux measurements from serial number 030005 (x-axis) vs the other
LASs (only the last two digits of the serial number are shown in the axis labels) for experiment H1. The grey
dashed line is the 1:1 line.
Figure 41: The scintillometer transect in Boudtenga in August 2008.
86
2.2.4 Sub-project S4: Surface, Soil and Groundwater
The work of this sub-project consisted of the collection and modeling of water fluctuation
data as well as the calibration of the SWAT model for a particular measurement station.
Vegetation water measurements and GIS work was combined to assess temporal soil
moisture dynamics in the Volta Basin.
Milestones achieved:
Root zone model that will adequately estimate soil water in the root zone from RS
data.
Automated delineation of surfaces of reservoirs and important reaches via
Envisat ASAR images, and of corresponding stored volumes.
Pedotransfer/ANN function derived for saturated hydraulic conductivity
Preliminary database on groundwater levels in northern Regions of Ghana (in
connection with I2)
Calibrated, validated physical model of groundwater recharge within UER
Surface temperature model and scaling methods (with S3)
Milestones not achieved:
Completed geomorphological profiles of key Volta tributary reaches
Automated generation of soil moisture fields for input to regional climate model
Not achieved due to lack of satellite data. The automated generation of soil
moisture fields was planned to work with data from the European Space Agency's
(ESA) Soil Moisture and Ocean Salinity (SMOS) satellite. Due to technical issues
ESA has not been able to launch the satellite yet which consequently means that
an implementation of satellite soil moisture estimates into a regional climate
model could not be realized.
Application of Envisat altimetry to derive near-real-time levels of Lake Volta and
larger upstream rivers
Reliable altimeter estimates have only come on-line very recently
Tested and verified saturated hydraulic conductivity and textural map of the White
Volta Basin (entire basin may require more time)
This aspect of the studies was not continued as the focus of the project shifted
87
Methodology and Research Results
In May 2006 the Water Resources Section of the TU Delft joined the GLOWA Volta
Project for the 3rd project phase. Contributions mainly focused on the Ph.D. research by
J. Friesen as well as on internship projects (J. van der Hoog) and master theses (J.
Smits, J. van den Berg). The research activities were mainly concerned with satellite
soil moisture estimations for West Africa and the influence of vegetation water onto soil
moisture estimations. Soil moisture information is a vital parameter for water resources
planning and food production. In particular for West Africa, where income largely
depends on rainfed agriculture, reliable information on available soil water is required for
modeling and prediction. Over large areas and, specifically, for data scarce regions,
satellite soil moisture estimates are required to obtain reliable information on available
soil water. This necessity for satellite-based soil moisture data has already resulted in
recent and upcoming satellite launches. Although satellite-based soil moisture estimates
have been globally available since the early 1990s, the satellite signal used to derive soil
moisture estimates, has yet to be fully understood. In this sub-project the interrelation
between vegetation water and satellite-based soil moisture estimates is investigated for
West Africa. Based on observations and a series of regional models the link between
vegetation and satellite signal was hypothesized and tested. New methodologies for
ground observations of soil moisture and vegetation water were developed, which
provide the means to design experiments for calibration and validation of upcoming soil
moisture satellites.
The different research activities dealt with remote sensing studies, extensive field work
of soil moisture and vegetation water, and modeling studies of the soil-vegetation-
atmosphere system. Results of the different research activities are presented in the
following order: (i) Spatial and seasonal patterns of diurnal differences in ERS
Scatterometer backscatter data for the Volta Basin and for West Africa, (ii) Hydrotope-
based protocol to determine average soil moisture over large areas, (iii) Tree rainfall
interception measured by stem compression, and (iv) Large-scale soil-vegetation-
atmosphere modeling for West Africa.
Spatial and seasonal patterns of diurnal differences in ERS Scatterometer
backscatter data for the Volta Basin and for West Africa
Imperative to the abovementioned research activities was the detection of diurnal
differences in backscatter data from Wind Scatterometer instruments onboard the
European Space Agency's (ESA) ERS-1 and -2 satellites. The ERS-1 and -2 satellites
collect data at about two to four times a week and at two times of the day, 10:30 am and
88
10:30 pm. The satellite backscatter data is the basis for satellite soil moisture estimates
provided by the TU Wien (http://www.ipf.tuwien.ac.at/radar/index.php?go=ascat). ERS
satellite backscatter data is mainly influenced by the geometry and by the dielectric
constant of the earth's surface. The dielectric constant can be seen as a proxy for water
content. Whereas over bare soil the water content of the topsoil layer is detected, over
vegetated regions the water content of the vegetation layer influences the satellite
backscatter as well. Figure 42 shows that the average backscatter data for West Africa
closely follows the general moisture distribution for West Africa with low backscatter
(equivalent to low moisture content) in the north, and high backscatter (equivalent to
high moisture content) in the south.
Figure 42: Average satellite backscatter distribution for West Africa from 1991-2000
Whereas the average backscatter depicts the general moisture distribution for West
Africa, the differences between backscatter data collected in the morning and data
collected in the evening shows different spatial and temporal patterns. The diurnal
differences in backscatter data have first been detected and published for the Volta
Basin (Friesen et al. 2007a). Results shown here show the diurnal backscatter
differences for West Africa (Friesen 2008b).
89
Figure 43: Diurnal backscatter differences for West Africa (differences in backscatter from 10:30 am and
10:30 pm)
Figure 43 shows diurnal differences derived from 10:30 am and 10:30 pm backscatter
data. In comparison with Figure 42 it can be seen that the patterns differ from the
average soil moisture distribution (especially over the Volta Basin). Next to the strong
spatial distribution (see Figure 43) a temporal distribution has been detected as well (not
shown), suggesting a strong link to vegetation water (Friesen et al. 2007a, Friesen
2008).
Hydrotope-based protocol to determine average soil moisture over large areas
The resolution of soil moisture satellites, such as SMOS and MetOP, is relatively coarse
(>100 km²), which brings with it the need for large-scale soil moisture information for
calibration and validation purposes. The developed hydrotope analysis helps (a) to
ensure statistically reliable validation, via reduction of the overall pixel variance, and (b)
to improve sampling schemes for ground-truthing, by reducing the chance at sampling
bias.
90
The hydrotope-based protocol was illustrated on the basis of two extensive soil moisture
sampling campaigns in the Volta Basin (Friesen et al. 2008a). At three sites with
different moisture regimes soil moisture was sampled during both dry and wet season.
About 200 soil samples were collected and analyzed for each site and during each
sampling period. Figure 44 shows the hydrotope distribution for the sampling site close
to Ejura, Ghana.
Figure 44: Hydrotope map at the Ejura study site
Results from three locations in the Volta Basin show that different levels of reduction in
overall pixel variance of soil moisture are obtained depending on the general moisture
status. With respect to the distinction between the different hydrotope units, it is shown
that under intermediate moisture conditions the distinction between the different
hydrotope units is highest, whereas extremely dry or wet conditions tend to have a
homogenizing effect on the spatial soil moisture distribution (see Figure 41). The study
confirms that well-defined hydrotope units yield an improvement at pixel-scale soil
moisture averages that can easily be applied.
91
Figure 45: Hydrotope unit separated vs. regular soil moisture distribution. PDFs of a sample soil moisture
distribution divided into hydrotope units (grey lines), as well as an overall soil moisture distribution (black
line) are shown.
Vegetation water observations
The spatial and temporal patterns of the diurnal backscatter differences in ERS data
suggested a strong link to changes of vegetation water. To quantitatively measure
changes in vegetation water an instrument was developed that can measure tree water
content and fluxes directly (Friesen et al. 2008b). Field campaigns in the Netherlands,
Ghana, Burkina Faso, Nigeria, and the USA have been conducted.
The measurement principle is best illustrated using rainfall interception as an example.
Interception of rain and snow by tree crowns can be a significant part of the water
balance. Rain, intercepted by leaves, that evaporates directly back into the atmosphere
may make up 10% to 60% of total precipitation. We make use of the fact that water or
snow intercepted by the crown compact the trunk; simply following Hooke's law (see
Figure 46). Basically, any mass change of the tree crown, such as water stored on the
leaves, in the leafy and woody biomass, as well as water stored within the tree crown,
can be detected and quantified.
92
Figure 46: Schematic view of elastic stem measurements
By measuring the compaction, the amount of water stored in the crown can be
measured. In practice, many problems have to be overcome before a good weight signal
is obtained. For starters, 1 kg of water stored in a small tree causes a compaction of
only 100 nm over a stretch of 1 m. Such small displacements can actually be measured
relatively easily with special potentiometers. The main source of noise is bending by
wind. By radially installing three sensors, wind effects could be accounted for as well.
Final measurement accuracies of 1 kg to 5g were obtained, depending on tree size.
Large-scale soil-vegetation-atmosphere modeling for West Africa
Modeling of the soil-vegetation-atmosphere system aimed at retrieving the water stored
in vegetation. Through the comparison of modeled vegetation water and diurnal satellite
data, the effect of vegetation water onto satellite soil moisture estimates was
investigated. Satellite backscatter data, used to estimate soil moisture, is available at
two times, in the morning at 10:30 am and in the evening at 10:30 pm. The difference
between satellite observations at the two retrieval times shows spatial and temporal
patterns that suggest vegetation water to be one of the main causes.
Modeling focused on two approaches: (i) a physical approach (Figure 47) and (ii) a
conceptual approach (Figure 48) based on findings from the physical model. The
physical approach models water flow from the soil through tree vegetation into the
atmosphere. Vegetation water is modeled diurnally, in 30 minutes time steps, for 2006.
The conceptual approach uses results from the physical modeling approach, namely the
response of diurnal vegetation water fluxes onto limited soil water availability, and
Displacement changes that are caused by interception, dew, evaporation, transpiration, wateruptake, growth, etc.
Steel Bolt to fix
instrument to the trunk
Potentiometer to
measure displacementchanges (sub-µm accuracy)
Quartz rod (1 m long)
as an extension for the potentiometer
Steel Bolt to fix
instrument to the trunk
120°
93
combines the different vegetation water fluxes with available soil water from a regional
soil water model.
Figure 47: Physical approach. Diurnal plant water fluxes as influences by declining soil water. On the left
water movement along a tension gradient from soil to tree into the atmosphere is shown. On the right, the
diurnal flux schemes depict soil water tension (ψsoil) and resulting plant water tension (ψplant)
94
Figure 48: Conceptual approach. Combined tree and grass drought periods as determined by different
drought definitions for trees and grasses
Results from the physical approach support the hypothesis that vegetation water is one
of the main causes for the detected satellite patterns (Friesen 2008 – chapter 4). Diurnal
fluxes of tree vegetation water respond to soil water availability.
Figure 49: Diurnal tree water flux in [g] during a period of declining soil water content. Green and red dots
show tree water storage at morning (green) satellite overpass times and at evening (red) satellite overpass
times
95
Figure 49 shows that under saturated soil water conditions the evening vegetation water
status is above the morning water status. When soil water becomes limited, the diurnal
flux pattern of vegetation water shifts and the evening vegetation water status drops
below the morning vegetation water status. This shift in the relation between morning
and evening vegetation water status corresponds to the temporal patterns detected in
the satellite backscatter data.
The conceptual approach uses the results from the physical approach, postulating that
under water limited conditions the diurnal vegetation water flux shows a shift in the
relationship between morning and evening vegetation water status (Figure 45). Using a
conceptual drought period concept (Figure 44) the results from Figure 45 are linked to a
regional soil water model.
Figure 50: Monthly averaged diurnal ERS backscatter differences (1992-2007) and monthly vegetation
drought period maps (2006)
96
The conceptual drought period approach (Figure 50) shows drought stress, and a
corresponding shift between morning and evening vegetation water status, over a large
area with high intensity in November. This area shrinks until February. The conceptual
drought period maps show the spatial and temporal distribution of droughts. In
comparison with diurnal satellite backscatter differences the drought period concept
shows good agreement in months of high backscatter anomalies (October to February).
The modeling results show that vegetation water can be seen as one of the major
causes that influence the detected diurnal satellite backscatter differences. In view of
future satellite validation campaigns and field studies, that are required to fully prove the
link between satellite backscatter patterns and vegetation water, it can also be
concluded that diurnal variations in vegetation water have to be included. For further
details of this study the reader is referred to Friesen (2008).
During the reporting period E. Obuobie carried out several research activities within the
White Volta River Basin at 3 different spatial scales, namely, the north-eastern part of
Ghana (the Upper East Region), the Ghanaian portion of the White Volta Basin, and the
entire White Volta Basin (Figure 51).
Figure 51: Map of the Volta River Basin showing the various spatial scales at which research activities took
place; the Upper East Region (area marked red), the White Volta Basin of Ghana (area marked yellow) and
the entire White Volta River Basin (area marked in dark green)
97
The research activities were done primarily for his PhD thesis and included:
1. Collecting water samples (rain and groundwater) and analyzing for chemical and
isotopic contents;
2. Collecting soil samples and analyzing for physical and chemical properties;
3. Installing and operating hydro-meteorological equipments such as automatic rain
gauges and pressure transducers;
4. Monitoring groundwater levels;
5. Collecting, cleaning and analyzing primary and secondary data on soil, climate,
stream flow, land-use/-cover, and hydrogeology;
6. Estimating groundwater recharge at the 3 spatial scales and evaluating climate
change impact on hydrological fluxes;
7. Writing up of PhD thesis and attending conferences and workshops
Figure 52: SWAT-simulated mean annual shallow groundwater recharge in the White Volta River Basin
(1980-1999)
Results of the chemical analyses of water samples collected reveal that monthly chloride
deposition in the Upper East Region via rainfall in 2006 ranged from 0.2 to 2.1 mg/l, with
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98
mean and standard deviation of 0.8 mg/l and 0.43 mg/l, respectively. Chloride
concentrations in groundwater ranged from 4.0 to 23.8 mg/l with mean of a 13.2 mg/l
and a standard deviation of 9.0 mg/l. Based on the variation of chloride concentrations
measured in groundwater, the estimated long-term annual groundwater recharge in the
Upper East Region was estimated to be 34-182 mm, with a mean of 82 mm. The mean
annual recharge represents 8 % of the long-term mean annual rainfall of 990 mm.
Analyses of water table fluctuations in the south of the basin (commonly referred to as
the White Volta Basin of Ghana) show that annual water-level-rise ranged from 1238 to
5000 mm in 2006 and from 1594 to 6800 mm in 2007. Based on standard values of
specific yield and the measured water-level-rise, the estimated annual recharge ranged
from 28.0 to 150 mm in 2006 and from 32 to 204 mm in 2007. The areal-weighted mean
recharge was 70 mm in 2006, representing 8 % of the annual rainfall (870 mm), and 92
mm in 2007, representing 7 % of the annual rainfall (1294 mm).
Figure 53: SWAT-simulated mean annual rainfall in the White Volta River Basin (1980-1999)
The hydrological SWAT model was calibrated (1986-1999) and validated (1992-1999) at
Nawuni for the entire White Volta River Basin. The simulated mean annual recharge to
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600 - 700
700 - 800
800 - 900
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99
the shallow groundwater was obtained to be 59 mm, about 7 % of the mean annual
rainfall (824 mm). Generally, the southern parts of the basin receive more recharge
compared to the northern parts (Figure 52).
This is reflected in the distribution pattern of rainfall and soil type. The south receives
more rainfall compared to the north (Figure 53) and has two peaks as against one in the
north.
The soil types in the north are high in clay content compared to those in the south
(Figure 54).
Figure 54: Texture of soils in the White Volta River Basin (Schuol et al., 2008, modified after FAO, 1995)
Using SWAT-simulated annual hydrological fluxes for the present time period (1991-
2000) as basis for comparison with the simulated future (2030-2039) fluxes it can be
seen that the variations in the fluxes increases as a result of future climate change.
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2.3 Cluster E Analysis of Long-Term Environmental Change
The cluster "Analysis of Long-Term Environmental Change" focuses on environmental
changes endogenous to the Volta Basin that evolve over decadal time scales. These
changes, such as alterations in land cover, soil degradation and loss of wetlands on
which many ecosystem services depend, reflect complex interactions and feedbacks
between climate, population density and economic activities. They affect the water
balance directly through the partitioning of surface water fluxes, and likely indirectly as
well through contributions to regional and global climate change. Land cover and land
use have a major influence on the water cycle in the Volta Basin. The observed
progression of land surface characteristics within the basin reveal the underlying
physical and anthropogenic factors driving land use change. Research done in this
cluster aims (a) to quantify and predict the evolution and future state(s) of the land
surface within the Volta Basin (b) to provide spatially- and temporally scaled land
surface data as input for models of land use change, regional climate and hydrology,
respectively (c) to develop and implement operational models of land use change within
the basin.
2.3.1 Sub-project E1: Automated Classification of Remotely Sensed Imagery
The Würzburg group provided data for the Phase II clusters L1/ Land use change
detection and quantification, L3/ Vegetation dynamics and L5/ Land use change
prediction model. Work for these clusters was continued in Phase III.
Milestones achieved
Completed processing and availability of RS products on a multitemporal and
multispatial basis for land use, climate and hydrologic models
Completed validation of land cover and land use algorithms using high resolution
remote sensing data/and or field observations
Development and implementation of up- and downscaling algorithms within the
RS image processing cycle
Completion of change detection map for the period 1990 and 2000 for the entire
GLOWA basin and land cover change between 2000 and 2006 for a subregion, at
spatial resolutions of 30-meter and 250-meter.
Estimation of Vegetation/land cover change due to anthropogenic impacts
completed for a sub-region in Northern Ghana
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Completed parameterization/assessment of vegetation change and land cover
dynamics within the Volta Basin, used as a basis for development of rule-based
algorithms of LUCC Models.
Milestones achieved with deviations
Completed retrieval of NDVI/EVI, LST, emissivity, surface cover, and tree density
values for the entire Volta Basin at spatial resolution of 250m to 1km for the years
1999 to 2009 using the MODIS AQUA and TERRA sensors.
The above variables were only processed from 2000 to 2006, since this time frame is
sufficient to infer variables for meteorological modeling and due to data
processing storage space limitations
Estimation of Vegetation dynamics due to climate variability complete.
No assessment between vegetation dynamics and land cover change was performed
since land cover change was validated with reference data and was utilized to
assess anthropogenic change rather than climate induced dynamics. Inherently
so, anthropogenic change can be termed under the global change, which already
includes climate and vegetation variability.
During Phase II of GLOWA Volta the remote sensing group of the University of
Würzburg derived Land Cover Change data for the year 1990 and 2000 as beat
versions for the Upper East area in Ghana (Landsat: 194/52, and 194/53).
However, to quantify land cover change in a standardized way for the whole Volta Basin,
primarily Ghana, Burkina Faso, Togo and Mali, T. Landmann, M. Schmidt, M Machwitz
and R. Colditz remapped the whole Volta Basin (400.000 km2) using the standard Land
Cover Classification System (LCCS) legend from the Food and Agricultural Organisation
(FAO) in Phase III. They used spatially explicit satellite data sets from 1990, 2000, and
2007/2008. Landsat and ASTER satellite data with 15-30-meter resolution was used for
the mapping; the spatial explicit data sets where augmented with 250-meter MODIS
(MODerate Resolution Spectroradiometer) satellite data sets for very dynamic land
cover features, such as wetlands and to improve the temporal data resolution. MODIS
has near to daily satellite overpasses13, thus making it possible to derive biophysical
variables not only for hydrological and climate modeling (see main results below), but
also for large scale and standardized land cover and land cover change mapping.
To feed the above hydrological and climate models they processed and analyzed daily
13 Barnes, W.L., T.S. Pagano et al. (1998). “Prelaunch characteristics of the Moderate Resolution Imaging
Spectroradiometer (MODIS) on EOS-AMI.” IEEE Trans. Geoscience Remote Sensing 36: 1088–1100.
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250-meter MODIS time-series. The MODIS satellite passes were corrected for „noise‟
such as clouds and shadows (Colditz et al., 2008). They also used the corrected MODIS
observations to improve the tree cover estimates that describe the Landsat mapped land
cover classes. Parallel to that the accuracy assessments of the Landsat tiles, for both
time frames, were assessed using over 1800 systematically collected field data points
on land cover in the Volta Basin. The field data was captured from 2006 onwards at
sites throughout Burkina Faso, Ghana and Mali. Some invariant field data points were
used to improve and recode the land cover data if the mapped data deviated from the
„observed‟ field data. For the 1990 data they used historic data observations and
topographic maps from the early 1990s, for the accuracies and the improvements
respectively.
To infer rates and magnitudes of land cover change in the 1990 and 2000 data set, they
used a change detection matrix on the thematic data. The matrix calculation allows for
change processes such as land cover modifications and transformation trends, rather
than mapping individual satellite image pixel based land cover changes (Landmann et
al., 2008). To improve the change estimates they also used high resolution ASTER
satellite imagery and MODIS data to infer land cover for the year 2007 and 2008. The
2007/2008 land cover was inferred not for the entire Volta Basin, since ASTER has a
limited overpass footprint and is not available free of charge. From 2003 onwards
Landsat data continuity was impaired by the malfunctioning of the instrument. Urban
areas and wetlands were mapped separately to most other land cover features, since
these two classes are challenging to infer from Landsat imagery and only spectral data
from MODIS time series metrics. Urban areas were predicted using 1-kilometer Defense
Meteorological Satellite Program (DMSP) night light intensity data, and wetlands were
predicted using 250-meter MODIS reflectance data in combination with topographic
variables. All three data trajectories, i.e. LCCS land cover from 1990, 2000 and
2007/2008 were resampled to 250-meter geometric resolution, and made available to
the GLOWA project partners and stakeholders.
Essentially the land cover trajectories were interpreted to render rates of change and
quantify their magnitudes. For this the remote sensing group of the University of
Würzburg derived change statistics and related these to the underlying land cover
change drivers. The land cover drivers were determined from non-linear functions to
socio-economic data. The driver and land cover change and driver relationships were
used for key results that will be employed in cellular automata models to predict land
cover scenarios under a variety of land management options (see also Landmann et al.,
2008).
In addition to the above, Net Primary Productivity (NPP) has been modeled over most of
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the Volta Basin, so as to render carbon dynamics and changes in carbon for improved
emissions modeling and possible reporting mechanisms, i.e. the REDD (Reducing
Emissions from Deforestation and Degradation) program. Climate variable such as
surface energy fluxes were also used in the NPP estimates and ultimately emission
estimates. The REDD estimates specifically were modeled/estimated in the context of a
M.Sc. study project in collaboration with the GLOWA Volta Project and for a study site in
Southern Ghana.
The main research results are made available in the form of publications and research
papers, including conference proceedings, data sets or products and ultimately spatial
statistics on the land cover change magnitudes, trends and lastly causalities. The
products are spatial data sets that are „housed‟ by a data portal, either in house at the
University of Würzburg‟s GEO dataportal (http://geodaten.fernerkundung.uni-
wuerzburg.de:8080/geonetwork/), or through the GLOWA Volta Geoportal on the
GLOWA Volta website (www.glowa-volta.de) or the BIOTA West Africa project data
portal (www.biota-africa.org).
The three data portals allow for metadata searches. The data products from this work
group are listed below and the 1990 and 2000 land cover data sets, derived from
Landsat, MODIS, 1-kilometer DMSP (Defense Meteorological Satellite Program), and
digital elevation data (at 90-meter resolution) are shown in Figure 55 and Figure 56
respectively. Figure 57 shows the distribution of land cover change processes for an
area in Burkina Faso.
The team at the University of Würzburg furthermore provided satellite derived
biophysical variables to the climate and hydrological working groups in the project
consortium. The variables were processed as 16-day satellite data composites such that
they were corrected for cloud and cloud shadow effects, and annual metrics on the
flowing variables were rendered: LAI (leaf area index), white sky albedo, LST (land
surface temperature), NDVI (Vegetation index) and Emissivity. The variables were
corrected using a software developed in-house (Colditz et al., 2008). The variables were
ingested into water balance estimation models for the Volta Basin, using remote sensing
dynamics on biophysical processes including downscaling of meteorological fields
(Wagner et al., 2008). The main results from this study show that remote sensing
variables could significantly improve the water balance assessments in the Volta Basin.
Pertaining to the carbon stock assessment for the Volta Basin, a NPP model was used
that uses eddy-covariance tower measurements from the GLOWA Volta Project sites as
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well as climate parameters from these sites. First results are currently being published14.
The NPP model results will be extrapolated to the wider region in the GLOWA Volta
Basin to estimate carbon stocks. Also in this context, a master thesis was initiated that
showed how satellite mapped land cover change combined with socio-economic data
can be used to estimate carbon loss in southeast Ghana. It was established that carbon
losses in southeastern Ghana were primarily through processes like complete forest
transformations. The results of the master thesis will be implicated for the REDD
program. Based on the carbon stocks loss data, the consequences of REDD were
modeled with the STELLA carbon model in cooperation with IUCN (International Union
for Conservation of Nature) and CIFOR (Centre for Integrated Forestry) 14
As an addition to the land cover maps provided for 1990, 2000 and 2007/2008, they
derived a “wetland occurrence” data layer for the whole Volta Basin (Landmann et al.,
2006). The wetland map is derived from 250-meter MODIS time series data, and
wetlands will be masked out that is excluded from the land cover change assessment,
as they are deemed to be too dynamic for land cover change mapping. The mapped
wetlands were accurately mapped from the 250-meter data and since wetlands are
important features for water budgeting models, the results will find utility in current and
future Volta water management assessments.
The main results from analyzing the mapped land cover change from 1990 to 2000 and
to 2007/2008, showed that most, i.e. 64 %, of the area of the Volta Basin (400.000km2)
was left „unchanged‟ which means that the land cover in 1990 remained exactly the
same land cover in 2000, and also in 2007/8. The second dominant change at 13 % of
the total area was transformation from natural vegetation to agricultural areas and the
third dominant change affecting 8% of the basins area was the transformation of natural,
mostly woody savanna, to natural herbaceous or bare surface. Modification processes
such as subtle changes in tree density over time accounted for 3% of the total area.
Largely the land cover change mechanism we developed and utilized in GLOWA,
showed that using LCCS land cover coding standards allow even the mapping of subtle
tree density changes over time and standardized LUCC processes instead of individual
pixel changes for only a specific land cover.
14 Sandker M, B.M Campbell (2009). “Exploring the effectiveness of integrated conservation and development
interventions in a Central African forest landscape.” BIODIVERSITY AND CONSERVATION 18 (11): 2875-2892.
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Figure 55: LCCS Land Cover for the GLOWA Volta Basin (1989-1991). The land cover was derived from
Landsat ETM+, MODIS, DMSP and SRTM imagery
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Figure 56: LCCS Land Cover for the GLOWA Volta Basin (2000-2001). The land cover was derived from
Landsat ETM+, MODIS, DMSP and SRTM
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Figure 57: Land Cover change processes from 1990 to 2000 mapped from satellite imagery for a region
(approx. 50 by 40 kilometers) in central Burkina Faso (West Africa). The land cover processes are illustrates
by colors. Blue for instance represents land cover transformation that is changes from natural vegetation to
cropland areas (over the observation period 1990-2000)
2.3.2 Sub-project E2: The Basin Wide Cellular Automata LUCC Model
This sub-project works on the modeling of cellular automation of land use - land cover
changes in hotspots areas of White Volta sub-basin. The work included the classification
of time series land use data, assembling data of potential drivers and the specification of
functional forms.
Milestones achieved
Identification of key drivers of land-use changes, and empirical rule extraction
Specification of the rule set
Milestones not achieved
Operational GV-CA model and pilot simulation runs
The rule sets from land cover driver and land cover change rate relationships
were not employed in Cellular Automata for operational scenario assessment.
The reason is that staff, that was knowledgeable in the CA programming, left the
GLOWA project during the later half of Phase III. The team in E2 also perceive
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this task to be the least important in the context of the third project phase, thus
towards the end of the project, priority way given to deriving a set of robust rule
set functions, under milestone 2 in the 3rd project phase.
Methodology and Research Results
The Basin Wide Cellular Automata LUCC Model aims to model land use change and
evaluate the main driving factors in the White Volta Basin. The modeling exercise by
Q.B. Le, L. Tamene and T. Landmann required multi-temporal images and socio-
economic factors that determine land use change processes. The main task
accomplished with regard to cellular automata modeling was the collection of images
covering the target area (from 1970s to 2000s) and gathering of available biophysical
and socio-economic data for the region around Tamale. The modeling exercise was
performed in February 2008.
The land cover codes were employed in cellular automata, so that land management
scenarios can be visualized. Prior to their employment statistics to infer land cover
change causalities were used, using non-linear functions and comparisons of the
satellite mapped processes to socio-economic data sets. Figure 58 below sums up the
statistical comparisons from an area in Burkina Faso, and the time frame 1990 to 2000.
The mapped land cover change processes are shown as circles, the absolute size of the
circles depicting their magnitudes in ha/year that was converted/modified. The three
dominant change processes are shown: Forest to croplands, forest to woodlands, and
woodlands to croplands. The relative contributions of the drivers within the circles
illustrate their significances, that is strength of statistical measures to the given change
mapped from remote sensing.
As evident in Figure 58, population density is the main driver for woodland to cropland
conversions, which constitutes the predominant transformation process observed.
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Figure 58: Main conversion processes as annual changes (% of all processes, 1990-2000, Burkina Faso sample
area), mapped using remote sensing observations. The relative significances of investigated drivers for each of
the mapped land cover change processes are s shown as fractions in the pie diagrams.
2.3.3 Sub-project E3: GV LUDAS. A High Resolution Agent-Based Model
The work of this sub-project was characterized by additional data collection, the
continuation of the database preparation, the verification of model variables and
parameters using multivariate statistics. Analytical case studies continued.
Milestones achieved
Relevant policy queries identified for selected typological community-catchments
Database updated for selected catchments
Statistical models estimated (land-use choice by typological household group,
agricultural productivity responses to water availability, soil erosion, and soil
nutrient status
Operational LUDAS programming complete
Milestones achieved with deviations
New algorithms specified for integration of bio-physical sub-models (runoff/soil
erosion/deposition, nutrient dynamics)
While a topological runoff model was implemented in GH-LUDAS, and an erosion
model was implemented in BF-LUDAS, the feedback link between agricultural
Forest to cropland Forest to woodland Woodland to cropland
Population density Distance to roads
Past expansion of woodland
Population density
Past cropland expansion
Past cropland expansion
Slope
Population density
~22.000ha/yr ~110.000ha/yr ~260.000ha/yr
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productivity and soil erosion could not be achieved due to a lack of long term data
sets.
Methodology and Research Results
Q. B. Le and his group produced an operational version of the multi-agent-based
simulation model applying GH-LUDAS modeling framework (Schindler, in press).
Figure 59: The conceptual framework of LUDAS for the coupled human-environment system
The model was applied to a meso-scale area in Upper East Ghana (Atankwidi
catchment with an area of about 150 km²) and a modeled resolution is of 30m x 30m. As
external factors, the introduction of small dams, credit schemes, changes in population
growth rate and annual rainfall were considered.
Another operational version of GV-LUDAS framework has been developed for
landscape-scale areas in the Ioba Province of Burkina Faso (Wahable and Sorians
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villages, each village covers about 50 - 70km2 each village) and the modeled resolution
is of 15m x 15m (Gleisberg, in preparation). The external factors considered in this study
are the introduction of agricultural extension and fertilizer subsidies for cotton cultivation,
demographic and annual rainfall change.
Simulation outputs consist of a spatially and temporally explicit land use/cover map,
visual graphs, and export files of selected land-use and livelihood indicators. These
convenient output visualization tools, together with the user-friendly interface of GV-
LUDAS, allow stakeholders to simulate and analyze selected scenarios, which can
serve as a basis for discussion and communication among stakeholders and policy-
makers. The effect of land-use change drivers (e.g. population growth, rainfall change
and policy interventions) on the overall economy of the community and on different
social groups could be gauged adequately. By providing multi-dimensional outputs in a
long run in response to the change of external driving forces, the model has a good
capacity in assessing the resilience and vulnerability of the social-ecological systems in
a comprehensive way.
During the specification and calibration of GV-LUDAS components, empirical analyses
and sub-model testing have resulted in not only calibrated parameters of household‟s
land-use behaviors, but also additive knowledge about socio-economic and landscape
patterns that should be useful for integrated natural management in the study areas.
The newly generated knowledge includes:
(1) the plausible and holistic classification of households in the study areas into
representative livelihood groups that form a basis for agent-based modeling as
well as aiding the identification of relevant target groups in land/water
management projects/programs.
(2) Identification of social, biophysical and policy determinants of household land-use
choices in the areas. In general, the results show that land-use decision
outcomes are livelihood typology-specific and both landscape and social
heterogeneities have a crucial effect on farmer‟s adoptions of land uses.
(3) Estimations of crop production functions (yield response functions) against not
only cultivation inputs (e.g. labour, fertilizers, pesticides), but also site conditions
(e.g. soil erosion risk, nutrient deposition and topographical wetness) and
management practice (e.g. inorganic fertilizer uses). As the relationship between
crop productivity and such factors were established, the multi-dimensional
production functions were used, as one among some others, for closing the
social-ecological feedback loops in the multi-agent-based model. The empirical
results also show that most of agricultural land in the areas are marginal to
inputs, thus soil conservation and land restoration are the urgent needs.
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These empirical findings are presented as self-sustained chapters in Schindler (in press)
and Gleisberg (in preparation).
The primary objective is to provide credible scenarios regarding the future state of the
Basin‟s land cover, to be used as input to the climate and hydrology models, and to
assess the impact of such changes on livelihood and economic activity. Beyond
providing support for linked climate and hydrological models, land conversion models
can be used as decision support tools for proactive land management on the local and
basin scales.
2.3.4 Sub-project E4: Land-use Change Predictions and impact on Land-
and water-use Policies
Milestones achieved
Identification of appropriate topics for scenario analysis in the selected sub-basin
and Communities
Assessment of local socio-political and institutional set up and stakeholder
analysis.
Identification of relevant stakeholders, interest groups and prevailing patterns of
resource management
Assessment of stakeholder managerial capacities, information needs and
potential
Mechanisms for decision support
Discussion of model output with relevant stakeholders
Scenario analysis using the identified policy issues
Development of a user-friendly model interface
Milestones not achieved
Collaboration in the calibration of the LUDAS/WaSIM-DS
The differences in time resolutions required for each model as well as the
implementation platforms proved to be too complex to overcome
Methodology and Research Results
The third phase of the GLOWA Volta Project matches the period of the main activities of
J. Schindler’s doctoral research, whose objectives were to develop an agent-based
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model for simulating land-use and land-cover change in the Atankwidi in Upper East
Ghana. This model, which is called GH-LUDAS (Ghana – Land Use DynAmic
Simulator), can be used by local decision-makers to test the impact of selected policy
interventions on socio-economic and environmental indicators to support communication
among stakeholders. The goal of the related PhD thesis was to document this model
and to analyze simulation results of selected (policy-related) scenarios. The research
activities for this task comprised the following four main activities: i) field work in the
study area to identify and collect relevant data, ii) data processing and analysis, iii)
programming work for building GH-LUDAS, and iv) simulations and thesis writing. The
first target of the field work aimed at the identification of relevant land-use-related social
and environmental factors and processes, including the identification of policy
interventions to be simulated by GH-LUDAS. For that purpose, informal interviews with
local stakeholders, including local farmers, staff of the Ministry of Food and Agriculture
in Navrongo, NGOs and policy-makers (e.g. chiefs), were conducted. In specific,
interviews with local farmers helped to shape the picture of land use and livelihood
strategies in the study area. Based on this background information, two socio-economic
surveys were conducted among 200 households in the Atankwidi catchment, one for
each cropping season. These households were selected on the basis of a spatial
random sampling approach. The surveys comprised household-specific data and plot-
specific data, which are data about every single farm plot of the household. Household-
specific data comprised household composition, household assets, livestock, income
pattern, labor investment strategy, non-farm activities, and policy-related data,
comprising access to credit and reservoir irrigation. Plot-based data comprised size and
shape of the plot, range of crops grown, amount of agricultural input and yield. The
plots, which amounted to 814 plots in total, were measured by using GPS waypoints,
which were imported in ArcView to determine the size and shape of the plots. Further, a
ground truth survey was conducted in the study area, during which land cover classes
were assigned to GPS waypoints, which served as a basis for the later development of a
land-cover image. Within the next main scientific activity, i.e. the data processing and
analysis, the collected data and other secondary data were used to calibrate variables
and sub-models for the later GH-LUDAS model. The basic idea behind GH-LUDAS is
that a collection of household agents, which are situated in a virtual copy of the actual
landscape, interact with each other and act upon this environment. Biophysical
processes represented by biophysical sub-models on the side of this landscape, work in
response to these actions by households which are governed by decision-making sub-
models. To derive such sub-models, at first a data base of relevant variables had to be
created. On the socio-economic side, collected data were processed and condensed to
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more meaningful variables, while on the biophysical side, ground truth data and
secondary data were used to create spatial data for the catchment area. These spatial
data comprised data within the domains of land cover, topography, soil, groundwater
and spatial accessibility. On the basis of both environmental and household data, sub-
models for GH-LUDAS were calibrated, including decision-making sub-models, an
income generation sub-model and biophysical sub-models. Decision-making sub-
models comprised decisions about labor allocation, agricultural input, type of land use,
use of technology and irrigation-related decisions, while biophysical sub-models
comprised agricultural productivity functions, a livestock dynamics sub-model and a
land-cover transformation sub-model. Within the third scientific activity, these sub-
models were programmed and embedded in an annual time-loop, and a setup
procedure mimicking the initial state of household agents and the landscape was
programmed. After finalizing the model code, simulations of selected (policy-related)
scenarios were conducted and documented in the 6th Chapter of the PhD thesis. The
first five chapters of the thesis deal with issues in land-use/cover change research
(Chapter 1), agent-based philosophy (Chapter 2), and a model documentation (Chapters
4, 5 and 6). The model documentation, together with data sources available at the
GLOWA Volta Geoportal, allows a full replication of the model.
The results of this doctoral study can be classified in two domains, i) the practical result,
which is the development of a decision support tool (i.e. GH-LUDAS), and ii) the
scientific result, consisting of simulation results of a range of (policy-related) scenarios
simulated by GH-LUDAS. The use of GH-LUDAS as a decision support tool is supported
by the choice of NetLogo as the programming platform, as it offers the possibility to
design a convenient user interface. A viewer located on the interface page of NetLogo
displays a virtual copy of the study landscape and allows monitoring the temporal
changes of land use/cover during time. Further, the setting of external parameters by
buttons and sliders allow stakeholders to play around with the model and to test their
assumption about future land-use and livelihood patterns. External parameters to be set
comprise parameters from the domains of dam construction, credit access, population
growth and rainfall change. Apart from the spatial output in the viewer of the interface,
the interface contains time-series graphs in which the performance of socio-economic
and land-use-related indicators is displayed during time. Spatial as well as temporal
output can be stored in output files and analyzed or processed in SPSS, Excel or GIS
software which support ascii formats. Using GH-LUDAS, selected scenarios were
simulated and analyzed on their impact on livelihood and land-use-related indicators.
For simulating land-use and land-cover change and related socio-economic
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performance in the study area selected scenarios were used to be run with GH-LUDAS.
Figure 60: Graphic User Interface (GUI) of the GV-LUDAS model for the Atankwidi catchment in the Upper
East of Ghana
Based on the analysis of the environmental, demographic and policy settings of the
study area, the range of external parameters of GH-LUDAS had been specified. These
include the size and location of dams, as well as the maximum area a household is
allowed to irrigate (in the drainage area of dams), annual percentage of households
obtaining credit, population carrying capacity and growth rate, and the selection of one
of the four rainfall scenarios as simulated by the CSIRO-Mk2 model within the IPCC
Special Report on Emmission Scenarios. Based on this selected range of external
parameters, scenarios were developed in a systematic and organized manner. First, a
baseline scenario was defined which reflects the policy settings as they were in 2006
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and assumed no changes in climate or demography. This baseline scenario was then
used to be compared to the pathways of other hypothetical scenarios. For this, each
external factor was shifted from the baseline gradually to form a scenario spectrum to
assess the impact of the change in this single factor. Each scenario was run five times
for a simulation period of 30 years with the base year 2006. Results show that in the
baseline scenario, average income increased from 1590 Ghanaian Cedis in 2006 to
1660 ± 50 Cedis in 2036, whereby the Gini Index of the income distribution increased
from 0.45 to 0.5 ± 0.004. The availability of credit greatly accelerated the growth in
annual gross income, leading to an average annual income of more than 2500 Cedis in
2036 for 10 % of credit access percentage. The construction of dams was considerably
less effective with 1750 ± 26 Cedis in 2036 for 40 constructed dams, each with an
irrigation capacity of 2.1 ha. The remarkable point here is that average annual income is
much more sensitive to a credit scheme, although the policy of dam construction is the
much more costly option in comparison to the credit scheme. However, a Gini Index
comparison of the two policies (0.513 ± 0.003 for credit, and 0.486 ± 0.004 for dams)
revealed that the dam policy is the better option in terms of income equality. In the
absence of policy interventions, cropland in the rainy season decreased from 62.5 % to
55.5 ± 0.76 % of the total area during the simulation period, whereas the implementation
of both policies further reduced this value by 1 % to 2 %. The dry-season land-cover
pattern did not show significant changes for the baseline scenario, as most of the
irrigable area had already been activated. The fraction of land-use types representing
cash crops (i.e. groundnuts and rice) significantly increased from 48.3 % to 52.2
± 0.38 % in the baseline scenario. Increasing credit access had a highly positive effect
on the cultivation of cash crops (56.9 ± 0.99 % in 2036). This shift to more marketable
crops is also reflected in the significant decrease of compound farming, the major
subsistence land-use type. Land-use change in the dry season did not include a shift
among land-use types, but rather the change of irrigation method. The number of
irrigating farmers decreased from 29.3 % in 2006 to 16.3 ± 0.11 % in 2036 for the
baseline scenario, as most of these farmers shifted to the use of motor pumps, which
allowed the cultivation of larger areas. This extreme shift to motor pumps can be
mitigated by an increase in annual credit access percentage.
From May 2006 until beginning of November 2007, the first part of the field research of
K. Gleisberg was conducted in the Ioba province in southwestern Burkina Faso. Within
this period, a household survey and the first plot-based surveys were conducted. For the
survey, 35 % of all households in three villages (Wahablé, Zouziégane, Téssiougane), in
total 111 households were selected. During the household survey, data regarding the
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demographic structure, migration, housing conditions, household and production assets,
livestock keeping, and access to extension services of the households were collected.
The plot based survey covered data on land use and land use practice, labor, yields in
dry season 2005/06. Further the location and size of every household plot, in total 964
plots, were measured with a GPS unit. In order to detect, describe and parameterize
relevant policy issues for scenario development within the agent-based model, semi-
structured interviews with NGO‟s, GO‟s as well as key informants were conducted. From
October 2006 to January 2007, two interns from the agricultural school of Matourkou in
Burkina Faso were supervised helping to collect data within a Water User Association in
Dano in order to evaluate a small reservoir project run by the Dreyer Foundation. From
November 2006 until March 2007 data entry from the first field trip about household
demographic structure, assets, extensions services and land use practice as well as the
measurement of plot sizes in Excel and ArcView was completed. During the second field
trip from March to June 2007, data on harvest at the end of the rainy season of 2006
and labor allocation were collected and entered. Further, the evaluation of the small
reservoir in Dano was revised and completed. Results of the evaluation were presented
to the Dreyer foundation and at the World Water Congress in Montpellier, France in
2008.
To improve our understanding of the complex human-environment system, compliance
or resistance to policies, the development of an agent-based model (ABM) requires
credible representations of micro-processes through comprehensive empirical analysis.
Thus, after finishing field research, the statistical data analysis to derive and
characterize farm households (household agents) and groups of households (livelihood
groups or agent groups) and estimate land-use choice (DECISION procedure) in the
study region started hand in hand with intensive literature review. Generally, the analysis
is based on a conceptual model derived from the Sustainable Livelihoods (SL)
framework. To capture topographical variables determining the distribution of soil and
water over the landscape, terrain indices were calculated using a combination of satellite
imagery, topographical maps, a digital elevation model and GPS measurements in the
field. Moreover, maps of land use/cover were elaborated based on data provided by the
University of Würzburg and a sub-model of land-cover conversion was elaborated. The
terrain data were used in estimations of agricultural yields (yield sub-model) to represent
land quality in the environment system (landscape agent).
As policy issues that have major implications for rural farm households and the natural
landscape in the study region, access to new technologies and knowledge on soil
conservation methods were identified. Accordingly, variables representing these policies
were created, namely access to agricultural extension services and access to mineral
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fertilizers. Guided by conceptual considerations of the impact pathways, indicators were
selected to measure the impact of the policy issues in terms of environment and
livelihoods.
All calculations and estimations were finalized by November 2008 accompanied by
intensive literature review. Since November 2008, the final writing process has started
and theoretical considerations, results and interpretations are put together.
In order to represent human heterogeneity in the agent-based model BF-LUDAS,
households in the study villages were classified based on household livelihoods. Taking
into account the local context, representative variables for each of the five capital assets
suggested by the SL framework were selected for the livelihood analysis. Running a
Principal Component Analysis, six key determinants of livelihood for farm households
were identified; namely non-farm income, labor, land resources, physical capital,
dependency, and education. Using standardized scores of the six principle components,
a k-means cluster analysis with k=3 then resulted in three differentiating livelihood
groups: cotton-based farmers, cereal-livestock farmers, and non-farm farmers. The
presented typology provides greater insight into livelihoods of households in the study
area and the factors that influence these.
The results of the analysis indicate considerable differences between the identified
household groups in the study villages in terms of their access to resources and
variations in their livelihoods. Each of the household groups faces different challenges to
support their livelihood. Access to land resources, labor availability, education, asset
endowment as well as income and income composition vary significantly between the
households groups. Moreover, household groups pursue different land-use practices in
line with their income and resource allocation strategies.
From a development-measures perspective, the insight into livelihoods and land-use
adoptions has implications for risk and vulnerability management in the region. Cotton
programs effectively reach only those households that have sufficient labor and
landholdings, which is not the case for the majority of the local community. However,
because of their orientation towards cotton production, these households are strongly
exposed to risk from global market-price fluctuations for both production inputs and
outputs. Farm households that are mainly based on cereals and livestock are often the
poorest in terms of access to resources for subsistence farming. These households are
characterized by low labor availability and a high dependency ratio. The labor shortage
results in insufficient application of measures for enhancing land productivity. For some
households, agricultural intensification through the application of chemical fertilizers for
cash crops and maize has emerged as a household strategy to improve the food
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security. However, this also means that these farm households are more exposed to risk
of increasing input prices. In this context, the introduction of credit schemes to aid
farmers‟ access to production inputs, such as observed in the study area, is helpful for
farmers in improving crop productivity as well as in reducing market risk. Investment in
non-farm activities is a promising strategy for those farm households lacking land and
labor resources for agricultural production. Moreover, stronger involvement in non-farm
activities leads to diversification of income sources and thus reduces the vulnerability
towards risks from climate and market. On the other hand, a strong orientation towards
activities generating cash income eventually results in a labor shortage for certain
activities in subsistence crop production. For example, non-farm households apply less
physical soil conservation methods and manure to their plots.
The logit models developed for the estimation of land-use choice indicate significant
determinants for land-use choice by heterogeneous livelihood groups in the study
region. In general, the results correspond to the scientific understanding of land-use
choice determinants. They suggest that multiple factors derived from theoretical
frameworks of various disciplines are needed to address the complexity of the system
and explain land-use choice in the study area adequately. Land-use choices of farm
households are driven by various socioeconomic characteristics of the household,
environmental conditions of the plots as well as land use-related policies. Moreover, the
analysis shows the relevance of using the plot as smallest unit. Linking higher level
characteristics allows the joint incorporation of biophysical, socioeconomic and policy
variables in the empirical analysis.
Regarding the land use-related policy factors, the results of the analysis suggest an
influence of these factors on land-use choice. However, the results show that the effects
of land use-related policy variables on the adoption of maize and cash crops do not
always work in the expected directions. Both, access to agricultural extension services
and access to fertilizers for non-cotton crops have only a limited potential to encourage
farmers to grow maize or cash crops respectively. The negative direction of the
influence indicates that the design of this policy factor is not appropriate to adopt maize
production. Despite the intense promotion of cotton cultivation including the provision of
chemical inputs and agricultural extension services, traditional land-use practices and
subsistence cropping are still very predominant aspects in land use and land-use
decision-making. This indicates that the adoption of new land-use practices and
agricultural inputs and their appropriate use needs to be sensitive not only to the
biophysical environment but also to the socioeconomic conditions of the target groups.
Because the adoption decision by farmers is a function of multiple factors, the
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knowledge of the role of each of these factors is essential to promoting new
technologies.
The analysis also revealed that heterogeneous livelihood groups have different
behavioral patterns regarding land-use decision-making. The differences concern
significant variables affecting land-use choice as well as the direction of these
determinants and the magnitude of the effect of variables. In general, the overall
livelihood strategy of the household groups is well reflected in their land-use choice
behavior.
The analysis of the natural environment has delineated spatial patterns of the landscape
variables. The results of the landscape characterization indicate that the territories of the
research communities are rather homogeneous. The terrain is flat ranging from 287 to
407 m and dominated by slopes between 0.5 and 3°. A land-cover classification based
on definitions of the Land Cover Classification System (LCCS) of FAO done at the
University of Würzburg and a reclassification done by Dr. Q. B. Le at the Center for
Development research has resulted in 12 land cover classes.
The sub-model AgriculturalYieldResponse which is built into landscape agents, performs
responses of landscape agents considering spatial heterogeneity and human agent
diversity (land management diversity). Because of little variations of the environmental
variables, their effect on agricultural yields is rather marginal. Among the land
management variables, labor input is the most important variable influencing yields of all
land uses.
The time period of this report embraces the whole PhD process for the thesis “Irrigate or
migrate? Livelihood adaptation in Northern Ghana in response to environmental
changes and economic challenges” of B. Schraven. The field research for the PhD
thesis started in March 2007 and was completed in June 2007. The research builds on a
farm household survey that was carried out in the North Ghanaian Atankwidi
catchement in April and May 2007. Its sample was based a survey that was carried out
by Julia Schindler shortly before. In addition to the survey, also semi-structured
interviews and expert interviews were carried out to get a more complete picture of the
research subjects.
The major credo of the above described research activities is that adaptation to climate
change is not necessarily only a process where NGOs, development cooperation related
agencies or governmental actors are mediating respective means to local people or
communities. It may also be the case that the last mentioned are even rather the main
drivers of these processes (although their capabilities are limited): in north Ghana,
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climate change and related factors such as land degradation have crucially changed the
conditions for rain-fed agriculture. Besides that, population growth and pressure has led
to a more and more continuous farming of available agricultural lands, which has
increased the problem of land degradation. The consequences are harvest failure and
decreasing yields which in turn has led to further impoverishment in Ghana‟s second-
poorest region. Currently, many young people migrated (seasonally) to Ghana‟s
wealthier south in order to supplement the agricultural livelihoods of their home
households. However, for about 15 years, many farmers have started to develop
specific forms of shallow groundwater irrigation (SGI) for vegetable gardening and
spread the related knowledge on that within their communities. This development has
largely contributed to a decrease in poverty levels and counteracts the traditional rural-
urban migration patterns – even though migration remains an emergency livelihood
option.
Although the irrigation farmers were able to profit from the development of the north-
Ghanaian road infrastructure and an increasing demand for vegetables in Southern
Ghana, more and more farmers are currently affected by market failures since they are
facing harsh competition from small-scale vegetable farmers from Burkina Faso. On the
other hand, Ghana also imports large quantities of cheap tomato paste from countries
where the production of tomatoes is highly subsidized. The global and regional
competition has started to seriously affect shallow groundwater irrigation, which was
originally developed as a very local and purely farmer-driven means to locally adapt to
environmental change.
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2.4 Cluster D Water Demand
The Water Demand and Management cluster encompasses the analysis of demand for
water resources, and by extension, the demand for investments and institutional
innovations required to improve the provision, the allocation and the productive value of
water across national boundaries, regions and economic sectors. The integrated water
resources optimization model of the Volta Basin is the primary tool for policy simulation.
This integrated model is also the fundamental interface between the linked atmosphere
– land surface – flow system domain and the social/policy domain. The overall objective
of the theme is to develop and to expand our software tools and methods of analysis in
order to enable us to describe, simulate and forecast the structure of demand for water,
and for important goods and services embodying water, at a range of spatial and
temporal scales. The goal is to permit an integrated analysis of the interactions between
basin climate and hydrology, water investments and management choices, growth in the
agricultural and energy sectors, and the overall health and performance of the economy.
Key issues are
• to describe, simulate, and forecast the spatial and temporal structure of demand for
water (on the part of society, industry, agriculture, hydropower, environment, etc.)
• to run integrated analyses of the interactions between basin climate & hydrology, water
investments & management choices, growth in agricultural & energy sectors, overall
health and performance of the economy.
• to create an integrated water resources optimization model encompassing interactions
and links between atmosphere, land surface, flow system, socio-economics, policy, etc.
• to provide models of water use & water value to support water sector policy decisions
at the regional, national and basin level.
•The analysis of demand for water resources takes place on various levels, e.g. across
national boundaries, regions, different economies, etc.
2.4.1 Sub-project D1: Agricultural Water Demand
The main focus was on the GAMS model on agricultural water demand in Ghana as well
as to replicate the existing MATA model of Burkina Faso for Ghana.
Milestones achieved:
Completed biophysical model specification for important rainfed and irrigated
crops in Ghana and Burkina Faso
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Completed specification of aggregate parametric production functions
Completed MATA model for Ghana
Linked MATA models for Ghana, BF
Linked regional MATA and integrated basin models
Model of investment in irrigation, forecast trends in area under irrigation by
technology type.
Methodology and Research Results
The researcher V. Afari-Sefa assumed duty as economist at the beginning of Phase III.
However, he left the project in 2007. During his assignment with the project an additional
collection of secondary data on estimates of the yield of major staples in the various
districts and regions was conducted with the aim of providing a clearer picture of the
correlation between rainfall regime and historical production over a range of spatial
scales up to basin level. The basic GAMS code for the macroeconomic modeling of
derived water demand in the agricultural sector (MATA) was received from our CIRAD
partner in Burkina Faso. The code was translated from French to English in Bonn. Data
requirements for parameterizing the model were then identified, and a strategy for
collection developed. Several discussions took place within the core macroeconomic
modeling team in Bonn to develop a road map for modifying the code to accomplish the
challenging task of aggregation spatial diffuse data to represent the basin scale. The
basic GAMS modeling code for the WAPP (D2) model was finally obtained from Purdue
University at the close of the year 2006 following a series of communication and
involving our staff and the Purdue team that developed the model. Pending exploratory
contacts with the WAPP Secretariat in Cotonou, VRA (Ghana) and Purdue University
regarding updated data on the West African Gas Pipeline installations and data for
WAPP-Zone A countries were also made. Preliminary analysis of data indicated that
with considerable modification, it is feasible to replicate the overall functionality of the
MATA model in Ghana as already in Burkina Faso. Progress in the modeling of
agricultural water demand has been constrained by the lack of geo-referenced census
data from the Ghana Living Standards Survey required for clustering and designating
the basin into representative farm types. Other challenges to contend with include data
reconciliation issues regarding biophysical model production function estimation in the
MATA model.
The PhD thesis of P. Woedem Aidam investigates the Impacts of Agricultural Sector
Policies on the Demand for Water Resources within the Volta Basin of Ghana, West
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Africa. In her second field research campaign in 2008, she collected primary in thirty
communities in the Volta Basin. Most of the secondary data she collected were obtained
from institutions related to water and agriculture.
The objective of the proposed research is to identify and - wherever possible - to
quantify and to model the factors that act to determine the demand for water in the
Ghanaian agricultural sector, both in the short- and long term. This analysis will show
which agricultural sector policies increase or decrease the demand for water, and what
measures can be taken to promote sustainable use of the water resource in the Volta
Basin. Specific objectives include the following:
To evaluate the impacts of specific government policies (irrigation, pricing,
subsidy, credit) and strategies, in combination with international market
conditions, on the domestic production (supply) of, and consumer demand for
important agricultural commodities; and the corresponding impacts on water
demand, within the Ghanaian region of the Volta Basin.
To build an economic model to simulate prospective water demand and supply in
the Ghana part of the Volta Basin and to maximize farmers‟ profit estimated as
the gross margin of the farm.
To calculate the optimal use of water for agricultural purposes within the Volta
Basin, to make available information about possibilities to restructure agricultural
production such that economic efficiency of water use can be improved
To simulate alternative policy prospect to assess the associated income changes
of agricultural producers.
The model being employed for the objectives is the MATA-WATER model; this model is
a partial equilibrium model that combines four different modules and links them together
in order to produce the results required. The three different modules are coded in
GAMS; these models are the production, consumption, macroeconomic and the water
module. These modules are linked together. The impacts of the agricultural sector
policies are used as scenarios and simulations are run to find the policy impact on
production, consumption and water demand.
The objectives of the PhD study by M. Mdemu were (a) the description of the multiple
use of reservoir water in the Upper East Region of Ghana; (b) the estimation of physical
water productivity for dry season crop water use based on soil water balance analysis;
(c) the estimation of economic water productivity for crop, livestock and fishery water
use during the dry season; and (d) the analysis of factors contributing to productivity of
water during dry season.
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At the irrigation schemes in Tono and Dorongo sample plots were selected and data
were collected on the amount of irrigation, irrigation frequency, daily soil moisture,
general crop development stages and crop yields. At scheme level, data on irrigation
diversion, surface drains, and cropped area were measured. Also a socio-economic
survey was conducted from sample household farmers to collect information on
production inputs and outputs. Irrigation water use efficiency at farm and scheme levels
for Tono was only about 16 % and 52 % respectively. In Dorongo, water use efficiency
was above 100% at scheme level. Although the water productivity values obtained in
this study concur with other reported findings from semi-arid sub-Saharan Africa,
potential exists for improving water productivity both at field, farm and scheme levels. At
field level water productivity could be improved by reducing deep percolation losses due
to over-irrigation during pre-wetting of the plots at the beginning of the cropping season
as well as by good plot management practices such as mulching to reduce direct soil
moisture evaporation from exposed soil surfaces that do not contribute to actual crop
water use. At farm and scheme levels water productivity could be improved by
minimizing non beneficial outflows, which account for more than 60% of water supply at
Tono. At Dorongo, water productivity improvement strategies at scheme level should be
based on factors that enhance crop yield, such as pest and disease control, choice of
crop varieties, timing of cropping activities and proper and optimal use of fertilizers.
Most of the farm plots in medium and small reservoirs are over-irrigated during the dry
season. Over-irrigation contributes to significant water loss and very low water use
efficiency particularly in medium reservoirs. The water productivity, both in medium and
small reservoirs were not higher than the few water productivity estimates available for
sub-Saharan Africa. However, water productivity values were below those reported from
outside sub-Saharan Africa. The contribution of irrigation water to the total value of
tomato production was high, suggesting that water plays a key role in dry season
farming. Although the imputed value of water differed significantly among the indicators
used within sites, it was not significantly different between sites. Location, crop yield and
price of the commodity were the main significant factors contributing to the imputed
value of water in this study. Although the value of water for livestock and fishery uses
were lower than that for irrigated tomato farming, such values provide important
information for seasonal planning of reservoir water resources management under
multiple water uses and demonstrate the importance of water allocation for the sectors
given competing uses.
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2.4.2 Sub-project D2: Non-Agricultural Water Demand
At the center of this sub-project stood non-agricultural water usages, such as urban
drinking water, water for gold mining and fish production. The case studies highlight
negotiation processes among various stakeholders within the water sector, specific
institutional frameworks as well as social-ecological independencies.
Milestones achieved:
Acquisition of technical data on proposed dams, reservoirs and hydropower
generation facilities within Ghana and Burkina Faso
Minimum environmental flow constraints defined for each critical reach in each
model time period.
Milestones achieved with deviations:
Completed per capita consumer surplus-type models of urban and rural domestic
water demand, respectively, with elasticity coefficients regionally adjusted
M³WATER has the capability to compute urban and rural domestic water
demand. Future water demands were calculated with population projections and
MDG norms,
Milestones not achieved:
Memorandum of Understanding with Purdue University/WAPP to enable sharing
of data and computational resources in the Volta energy sector
input-output and water accounting matrices for Ghana (this will probably not be
realized fully within Phase III)
Methodology and Research Results
The focus of the PhD project by D. Spalthoff stressed on urban water management in
Ghana and especially the role of NGOs/ civil society. Two poor urban areas in Accra
were selected for this research: Old Fadamah; an informal settlement-slum and Sukura,
a formal settlement. Preliminary findings concern the current state of water supply in
Accra. Water is very scarce in Ghana‟s capital. Water treatment capacities have not
been expanded significantly during the last decades; a period in which the city grew
enormously. It is estimated that the supply, which is provided by 2 water treatment sites,
Weija and Kpong, meets only 60% of the demand. Actors use different strategies to deal
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with the situation: While middle class households and industry invest in private
infrastructure (water tanks, pipes, pumps) and buy the water from private tanker
operators, the sector of urban agriculture uses mainly wastewater, and poor areas have
seen the development of small-scale water entrepreneurs (SSWE) who sell water in
buckets. The price paid for one bucket differs from area to area; we estimate that areas
with bad or no public infrastructure, where the pipes are laid by the SSWE themselves,
the price is significantly higher. The relationship between the water vendors and the
public agency responsible for urban water supply, the Ghana Water Company Limited
(GWCL), is highly informal. Nevertheless, SSWE have to deal with the GWCL, because
it provides the only source of properly treated water in Accra. The GWCL itself is under
high pressure to deliver better services, which lead to the outsourcing of the company‟s
top-management to a Dutch-South African enterprise, Aqua Vitens Rand Limited
(AVRL). Of further interest are (a) coping strategies of households and (b) the role of
civil society/ NGOs and business associations in the negotiating urban water supply with
the GWCL.
In September 2007 Mr. Spalthoff left the ZEF PhD program for an appointment with the
GTZ in Burundi. To ensure the usefulness of his primary data for the project, a research
report was delivered and the data was archived.
During a fact finding mission in August and September 2006 a field survey was
conducted by J. Hauck. The field trip had the purpose to get an idea about the
relevance of the topic fisheries and fisheries management in small reservoirs. The main
question for this first trip was: Do people use small reservoirs for fisheries and if yes how
is the resource managed. Therefore, 72 reservoirs, dugouts and rivers were visited and
59 interviews were conducted. Interviews were conducted with both individuals and
groups, most being fishermen and fish traders, In addition, interviews were also hold
with scientists, and technical and extension staff of the Ministry of Fisheries.
Based on data collected during a field trip in 2006, three reservoirs in the Upper East
Region of Ghana were selected for in-depth studies on their social-ecological systems
with the focus on fisheries. From January to August 2007 various types of data were
collected from the three reservoirs selected. Information to describe the ecosystems of
the water bodies was collected at three different points in time, February, May and July.
The data collected describe the morphometry of the reservoirs, water level fluctuations,
seasonal availability of nutrients and other factors such as oxygen, temperature, ph,
water plants, etc. These factors are influencing fish stocks and thus fisheries activities
and other water uses. Furthermore, two fish stock assessments per reservoirs were
carried out and will be analyzed together with the information described above. In order
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to describe and understand the social issues of fisheries and fisheries management in
the communities attached to the three reservoirs mentioned above, socio-economic data
were gathered with questionnaires for fishermen, fish traders and consumers. In addition
general community data were collected, like perceptions of wealth categories and local
resources maps were established and timelines with the histories of the reservoirs were
obtained. Problem and strategy rankings as well as influence network maps were drawn.
Starting in September 2007, the data was entered and processed using software such
as SPSS, MS Excel and Word or ArcGIS. In this analysis, data gaps were identified in
order to prepare another field trip with the purposes of collecting the missing data
wherever possible, and presenting the preliminary results to the communities, to the
Ministry of Fisheries and the GTZ, which started a pilot project for fisheries
enhancement in Northern Ghana.
As statistical analysis of ecological data is very difficult due to incomplete data and a low
number of case studies it was decided to use local expert knowledge in order to rank
factors that influence fish production in the reservoirs. A range of group discussions with
various experts, ranging from local fishermen to Ghanaian fisheries scientists, were
conducted and the mapping of influence factors proved to be a useful tool to supplement
the data sets. Other data collected were the dissolved oxygen levels of the three
reservoirs in a 24 hour cycle as well as the biological oxygen demand. Furthermore data
were collected on fish catches drawing on the memories of fishermen in order to get an
overview over average catches as well as differences in catches of 2007 and 2008.
After this second field trip, which took place from mid-March to mid-May, the data were
entered and processed using various software and methods. The time until the end of
the project was used to analyze data and write-up as well as presenting research results
and preparing publications.
Preliminary results of the research show that the social systems of fishermen and other
reservoirs users and the ecological systems of the reservoirs are closely linked and
influence each other. Furthermore the findings present fishing and trading of fish as
important livelihoods in the Upper East Region of Ghana. In three of the four villages
more than 15% of the adult male population are fishermen, with at least one fisherman
in every second household. In the dry season fishing in combination with gardening
becomes their main income source and 75% of the fishermen fish at least 5 days a
week. Trading fish is another important livelihood for many women who fry or smoke-dry
fish from the rivers or dams. In the dry season these women report an average income
of over 100 Cedis a month, which contributes in many cases more than 50% to the total
household income. The steadily increasing demand for fish further shows that fish is a
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very welcome addition to the menu. The rising demand for fish is increasingly met by
iced fish and small dried fish from Southern Ghana. The importance of these
commodities is reflected by a growing number of traders as well as consumers. Many of
these consumers belong to the poor strata of the society who cannot afford to buy meat
and rely totally on fish as source of protein. For a number of reasons the price for all of
these commodities is rising and it becomes evident that the supply from local resources
must be sustained and if possible increased. This was recognized by the Government of
Ghana which established a new Ministry of Fisheries in 2005 and enhanced fisheries
management and aquaculture was included in the country‟s Poverty Reduction Strategy
Paper. Nevertheless, the analysis shows a lack of training through local extension
workers which is necessary for building and supervising fishermen associations. The
associations are essential for sustainable resources governance.
Unfortunately, no community could be found with a functioning fishermen association.
Consequently, one of the main research question had to be reformulated into “What are
the reasons for the weak performance of community based management?”. A look into
history and the analysis of networks show that clashing traditional, governmental, and
participatory management strategies as well as generation conflicts overtax the
capacities of the communities to cope with management responsibilities. Organizational
problems and difficulties in the implementation of even the simplest, well-known
management rules, such as compliance with the ban on small meshed nets or close
season, are some of the consequences. The few attempts of science and policy to
improve the situation focused on technical solutions to increase fish production and
neglected problems of implementation.
However, missing or failing management is not the only factor influencing fish
production. The inclusion of local knowledge helped to rank the availability of nutrients,
changing rainfall patterns and the water volume of the reservoir as major ecological
factors influencing fish production. Water temperature, species composition or fish
disease for example were not mentioned to be highly influential. The integration of
scientific analysis and local knowledge proved to be useful to supplement and validate
research findings.
If cooperation between science, politics and local stakeholders can be established to
overcome the disenchantment with management, fisheries in small reservoirs has a
great potential to support the adaptation of the rural population to climate change.
W. Tsuma undertook his PhD research in the gold mines of Western Ghana where he
investigated the negotiation patterns between various actors in the sector. He was
interested in explaining the behavior of groups, e.g. civil society groups, local
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communities, research institutions, government agencies, media groups, in meeting
their goals within the sector. This research was based on the premise that continued
social and ecological problems in mining areas result from the competition between
various actors who pursue conflicting interests in these mining areas.
Specifically, his research activities sought:
a) To identify and map out the various actors, their roles and respective interests
within the Mining sector in Tarkwa area of Western Ghana.
b) To probe and identify the “spaces” and ”drivers“ where negotiations take place
and decision making is influenced respectively to meet the interests of local
communities, mining companies and the government within mining sector.
c) To investigate into the various modes of engagement within these negotiations as
well as identify the bargaining strategies and tactics employed to shape positions
and interests within the negotiation space.
d) To explain how various actors meet their interests and influence decision making
in their favor within the gold mining sector in Tarkwa area.
The main results of his research included:
1. The social and ecological problems associated with the mining sector are a
product of complex interaction between multiple actors within the mining sector.
These actors possess competing interests and in possession of differing power
abilities that not only determine the resources being accessed, but who gets to
benefit from the extraction investments.
2. Multiple interests by multiple actors influence decision making within the mining
sector. This includes, NGOs, mining companies, Chiefs, Universities / research
institutions, traditional authorities, government agencies and politicians. These
groups of actors are interest groups in themselves and act with an aim to meet
specific goals.
3. Decision-making within Ghana‟s mining sector is therefore an outcome of
unequal power struggles between these groups of actors and not the idealized
government legal systems of decision-making. In this case, the distribution of
benefits emanating from the mining investments is determined largely by these
power struggles more than anything else.
4. Patterns of exchange and benefit distribution within the mining sector is shaped
by strategic groups. Strategic groups emerge as an outcome of the unequal
power struggle within the mining sector. One common composition of strategic
groups is University Lecturers, NGOs, Mining Company Officials and Traditional
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Authorities, who not only determine the patterns of exchange, but also influence
decision making within the sector.
2.4.3 Sub-project D3: Integrated Demand Simulation Framework
Although preliminary and major activities in support of the data and modeling needs of
the Integrated Modeling sub-project have been going on in the past two phases of the
GLOWA Volta Project, the design and implementation of an integrated mathematical/
computer programming model were just started in the last quarter of 2007 with the
arrival of two new economists
Milestones achieved:
Completion, testing and application of the integrated economic-hydrologic
optimization model for the Volta Basin; and for important sub-regions including
the White Volta Basin
Development, testing and application of a linkage between the integrated
framework and agricultural economic sector models of Ghana and Burkina Faso
(MATA)
Development and testing of model linkage and data exchange protocols for the
models described above at basin scale using MM5-WaSIM output.
Milestones not achieved:
Completion of the prototyping exercise linking GAMS as WaSiM ETH at
catchment scale, Atankwidi (Upper East Region) (2006)
The economists did not appreciate this meso-scale approach and thus decided to
focus on the entire Volta Basin with a different approach.
Development and/or adaptation, testing and application of a linkage between the
integrated framework and engineering energy supply and distribution model(s) for
the Volta River region (WAPP).
Inclusion of additional groundwater mass balance equations (2006)
Sub-surface water was neither added to the VB-WAS or the M³ WATER model,
because the source of groundwater data for the entire basin is too poor.
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Methodology and Research Results
The sub-project involved three major activities of N. Perez: 1) estimation of major water
demand in the basin – domestic, industry, agriculture and hydropower; 2) construction
and calibration of the economic model coded in GAMS; and 3) integration of the
hydrologic and economic models to form the M3WATER decision support system, and
validation of the integrated model.
The first 50% of the working period (10 of 20 months), was devoted to the first two major
activities, while the second half until the end of the project in May 2009 was
concentrated on model integration, validation and construction of user-friendly interface.
In the last leg, an operational computer-based decision support system, M3WATER, has
been finalized and used in policy analyses – reported in a policy brief „Irrigation
Investment Policy in Volta Basin – an Application of M3WATER‟.
M3WATER can be used to analyze a range of investment and development policies that
affect the allocation of water in the basin. One such policy is investment in irrigation.
Expansion in irrigation area increases demand for water for agriculture and decreases
the volume of water that reaches Akosombo dam (in Lake Volta). The policy question
therefore is whether society gains more in terms of additional benefits from agriculture
due to irrigation expansion as compared to the „sacrifice‟ involved in the decline in power
generation due to reduced water in Lake Volta. Or similarly, are the net benefits to
society from expansion of irrigation positive?
A preliminary analysis of a 10 % annual increase in irrigation area (from 2005 base
values) starting in 2006 to 2040 using M3WATER shows that around 27 billion m³ of
water would be diverted to agriculture. This means a reduction of the benefits from
power generation of about US$ 369 million. However, benefits from agriculture from this
policy are estimated to be at US$ 6,426 million, for a net benefit of around US$ 6,057
million. This analysis and results are part of the policy brief - „Irrigation Investment Policy
in Volta Basin – an Application of M3WATER‟.
Since his employment in late 2007, A. Bhaduri has contributed in the further
development of a decision support resource (M3WATER) that will help in inter-country
inter-sector water allocation in the Volta Basin. M3WATER will integrate knowledge and
provide decision support for the planning, management and use of water resources in
the Volta Basin. The model can simulate the impact of any policy, climatic, demographic,
and socio-economic factors affecting the sectoral markets of the different water-using
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sectors - their effects on the resulting optimal water allocation among these sectoral
water users in the entire basin.
The decision support resource is currently functional with limited policy options.
However, water demand in the basin has been projected (country wise) over the next
thirty years. The results are available in the GLOWA Volta Database. The research
results are summarized in two papers.
1. Scope and Sustainability of Cooperation in Transboundary Water Sharing of the
Volta River
The paper examines the benefits and sustainability of such self enforcing cooperative
arrangements between Ghana and Burkina Faso given stochastic uncertainty in the river
flow. The findings of the paper suggest that at the present condition, the marginal benefit
of Burkina Faso from increasing the water abstraction is much higher than that of
Ghana‟s marginal loss. However, the paper finds that if both countries‟ water abstraction
rates are at a much higher level, then the marginal loss of Ghana increases
tremendously from similar increase in water abstraction rate by Burkina Faso. Under
such circumstances, there is an opportunity for Ghana to provide side payments in
terms of discounted export price of power in order to motivate Burkina Faso to restrict
water abstraction.
2. Climate Change and Cooperation in Transboundary Water Sharing :An Application of
Stochastic Stackelberg Differential Games
In this paper it is demonstrated how countries can cooperate in transboundary water
sharing in a sustainable way, given the impacts of climate change. In the framework of a
stochastic Stackelberg differential game, it is shown that issue linkage can facilitate
cooperation among the countries in the event of climate change. The case of water
sharing of the Volta River is illustrated between the upstream and downstream country,
Burkina Faso and Ghana respectively, where Ghana faces a tradeoff of water use
between agriculture in the north and production of hydro energy in the south. The results
indicate that during cooperation, Ghana will have an opportunity to increase its water
abstraction for agriculture, which has remained largely restricted. It is also shown that
the equilibrium strategies in the long run steady state distribution are stable even with
increasing variances of water flow; and the optimal value for the water abstraction rate
of Burkina Faso will decrease or increase with the increase in variances during low and
high level of cooperation respectively.
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Research activities of B. Barbier were focused on 5 different modeling approaches:
- Mata model for Burkina Faso and Ghana
- Bioeconomic model at the watershed level in the Pontieba sub-watershed (close to
Dano)
- Bioeconomic model at the watershed level in the Tougou sub-watershed in the Sahel
- Dynamic simulations of the Volta Basins in Burkina Faso with a hydro-demographic
model.
- Hydro and thermal energy dynamic model for Burkina Faso.
- a farm typology of burkinabe vegetable producers using a large burkinabe database
In addition, he also participated in the M3WATER modeling effort with N. Perez.
The research results of B. Barbier include new simulations for the Volta Basin with the
Mata model. The model also includes Ghana. Together with his PhD students he also
produced new results for the 3 others models developed at smaller scales.
- The Pontieba model developed with I. Dabiré shows the impact of seasonal forecasts
on farm incomes in a small watershed.
- The stochastic simulation developed by T. Mandé in the small sub-watershed of
Tougou shows how small scale irrigation reduces risk and allow for more rainfed crop
development.
- The simulations with the energy model developed with B. Kanazoé show
hydroelectricity and thermal energy compete to satisfy future national demand.
Scenarios with caps on carbon emissions show the tradeoff between environment and
economic efficiency.
- Another decision support system was developed using Excel and rules to assess the
impact of population growth and increasing demand on Burkina‟s water balance.
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2.5 Cluster C: Participatory Decision Support and Coordination of
Technology Transfer
The GVP has developed a number of different models and tools for the assessment of
the effects of diverse bio-physical as well as socio-economic and institutional changes
on the hydrological cycle as well as water allocation within the Volta Basin. To ensure
the sustainable use of the developed decision support technologies in the Volta Basin,
the GVP, together with the United Nations University (UNU) and the International Water
Management Institute (IMWI), has formed a consortium that facilitates the transfer of
technologies to the basin. The consortium organizes the necessary capacity building
activities that will enable local partners to make use of the GVP products. In a series of
workshops and trainings, stakeholders from government agencies, research institutes
and civil society in Ghana and Burkina Faso are trained in the use of different decision
support tools and the use and maintenance of GVP’s (meta-) databases.
The GVP has engaged in lively dialogues with a variety of stakeholders in the water
sector of the Volta Basin. In the beginning, knowledge exchange helped GVP scientists
to gain an understanding of the mandate, interests and needs of different stakeholders
and to trace and obtain already existing data and information. Since GVP scientists have
developed a variety of scientific decision support tools, data bases and a broad
repertoire of bio-physical, socio-economic and institutional knowledge, the GVP is using
the established partnerships to share its products.
As different stakeholders have different information needs and knowledge processing
capacities, the GVP has developed a diversified knowledge exchange approach.
Stakeholders with sufficient institutional and scientific capacity (government agencies,
research institutes and partially NGOs) are provided access to project databases and
are trained in the use of the advanced decision support resources the project has
developed. Knowledge exchange with other stakeholders is focusing on particular
issues (e.g. irrigation, hydropower) and is trying to make scientific findings available in
formats that take into account the capacities of local administrations, civil society and
actual water users.
2.5.1 Sub-project C1: Participatory Decision Support and Coordination of
Technology Transfer
Subproject C1 tries to better understand water-related negotiation processes at different
societal levels (local, regional, national) and to identify how the needs and capacities of
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different societal stakeholders can be addressed by the GVP during its capacity building
and knowledge and technology transfer activities.
Milestones achieved:
Selection of case studies completed and key dilemmas or conflicts formulated in
requirements analysis
Negotiation processes in case study areas understood and particular patterns
and needs for knowledge sharing identified.
Analyzed conflict resolution process among important strategic groups and actors
in the water sector on the national level and determined partners and
mechanisms for the cooperation with the civil society.
Carried out workshops and consultations with relevant actors from civil society
providing information about different information needs and the demand for
decision support within the civil society and evaluating validity of DSS outputs.
Milestones not achieved:
Protocol created based on insights from consultations and workshops defining
public access to the GVP DSS and the forms of information needed by the
various actors.
Antonio Rogmann has developed a protocol defining access to the GVP data /
database.
Methodology and Research Results
Activities of W. Laube in Phase III were mainly related to knowledge exchange with
various stakeholder groups in the Volta Basin and the communication of research
results in a wide range of workshops and conferences. Workshops had different
objectives: to assess local knowledge, to share research results and to build capacities.
Workshops were held in Bolgatanga and Accra, both in Ghana. The workshops in
Bolgatanga targeted local stakeholders such as farmers, local agricultural- as well as
water-administrations and Ghanaian scientists. Farmer- and multi-stakeholder
workshops were organized to generate knowledge and data for agent-based-modeling
(LUDAS) and to evaluate realistic policy scenarios for modeling purposes. The impact of
climate change in the White Volta Basin, local adaptation via different types of irrigation,
and the socio-economic as well as environmental consequences of such adaptation
were discussed.
Two civil society workshops organized in Accra assessed the capacity of NGOs in the
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water sector to benefit from the scientific results and the decision support tools
generated by the GLOWA Volta Project. Another workshop in Accra, organized in
cooperation with GTZ and IMWI, focused on the impact of climate change on the
generation of hydropower plants in Ghana. During the workshop, climate change
scenarios developed in the GLOWA Volta Project were discussed with various
stakeholders from government institutions as well as the civil society. Other research
activities focused on the local adaptation to climate change in the White Volta Basin
and, apart from qualitative research and farm monitoring, included a survey of 200
households engaged in shallow groundwater irrigation in the White Volta Basin.
The workshops organized resulted in lively knowledge exchange with local stakeholders
as well as with Ghanaian scientists. The workshops are documented in reports available
from the GLOWA Volta homepage. Together with PhD research results, the workshops
showed the limited interest and influence civil society has on water resource
management in the Volta Basin, with exception of the drinking water sector. While rural
drinking water provision partly depends on (international) NGOs whose current
management approaches demand civic engagement, and the attempted privatization of
urban water supplies met large public opposition, other domains of the water sector,
such as dam building, water pollution and mining encounter less civic engagement.
Research on local adaptation to climate change clearly showed that farmers in the White
Volta Basin have largely started to engage in irrigation activities as a means of climate
change adaptation. The production of irrigated vegetables for the national market allows
them to mitigate risks resulting from increasingly unreliable rains during the rainy
season. Irrigation could be shown to positively affect local livelihoods as it contributes up
to 40% of the agricultural production and reduces the need to migrate during the dry
season. However, research has also highlighted limits of adaptation that result from
severe marketing problems resulting from increased regional (ECOWAS) and global
competition. GLOWA Volta research on climate change adaptation is informing two new
research initiatives by the CGIAR (CP 65: “Contribution of informal shallow groundwater
irrigation to livelihoods security and poverty reduction in the White Volta Basin: current
extent and future sustainability”) and the BMZ/GTZ (Re-Thinking Water Storage for
Climate Change Adaptation in Sub-Saharan Africa) in which ZEF is involved.
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2.5.2 Sub-project C2: Transboundary Water Management
The process, actors and challenges of transboundary water management between the
riparian countries of the Volta Basin was analyzed. A case study on local transboundary
management practices was started in 2007.
Milestones achieved:
Comprehensive, annotated review of all projects and activities involved with
transboundary water management in Ghana and Burkina Faso
Summary of recommendations for institutional framework and legal arrangements
for transboundary water management, to serve as catalyst for transboundary
cooperation in the Volta Basin.
Definitive review of laws and regulations in the water sectors of Ghana and
Burkina Faso which address or influence transboundary water management, with
discussion of any major shortcomings and possible remedies
Milestones not achieved:
Analysis of case studies in rural areas where successful transboundary
cooperation in management of water resources has been realized locally (e.g the
ECOWAS/FAO Oncho Transborder Project, Bagré Dam)
Workshop involving water sector actors representing a range of geographic
scales and jurisdictions, to develop joint strategies and communication structures
and to address the plural Legislative Framework for Rural Water Management in
Africa
Methodology and Research Results
In 2006 E. Youkhana presented papers on “Virtual water Trade” and “Transboundary
water management in the Volta Basin” at international conferences in Bonn (June 2006)
and Ciudad Real, Spain (May 2006). A PhD student was selected and supervised who
was supposed to conduct a study on the hydro-political framework of water
management in the Volta Basin, but unfortunately left the project before starting her field
work. In 2007, the evaluation of “The transboundary water resources management
regime of the Volta Basin” was sub-contracted to the Water Resources Commission of
Ghana, and documented in a jointly prepared report. A glossary on actors and
institutions in the water sector of Burkina Faso was published and presented at Dano,
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the training Center of the Dreyer Foundation in Burkina Faso by the co-author Birguy
Lamizana. Together with L. Zug the GLOWA Volta literature data base was completed
and transcribed to a reference manager.
In 2008, the interactive institutional map on actors and institutions in the water sector of
Ghana and Burkina Faso was finalized together with P. Wittkötter and included into the
GLOWA Volta homepage. Two Master students from the University of Ghana (Legon)
and the University of Cape Coast, Center for Development Studies, who carried out
research on transboundary water management in the White Volta sub-basin in Northern
Ghana were supervised during their field trips and thesis writing. M. Asaah from the
University of Ghana completed his thesis in 2008. The thesis of T. Atinga from the
University of Cape Coast is still pending.
During a field trip in May 2008 a study was conducted on actors, networks and
communication structures in transboundary flood management in the Bawku border
region taking the example of the flood disaster in 2007. A report was written and the
main results presented at the International GLOWA Conference in Ouagadougou in
August 2008 together with C. Biney, executive director of the Volta Basin Authority. In
March 2009, the M³ Integrated Water Allocation Model was presented to invited
stakeholders in Accra.
A study by B. Ampomah, B. Adjey and E. Youkhana about historical and recent
development in transboundary water management has looked at the water resources
regime on the Volta Basin focusing on cooperation among the riparian states particularly
Ghana and Burkina Faso. The initial efforts of cooperation that led to the formation of
the Permanent Joint Commission on cooperation was a good start but did not sustain
the momentum for cooperation. Over the years, external influences in the form of
international actors and non-governmental organizations through several projects
formed a basis of cooperation between Ghana and Burkina Faso on the management of
the resources of the Volta Basin. These efforts were however mainly outside the realm
of the governments.
Several socio-economic and political interests and concerns in transboundary water
resources management between Ghana and Burkina Faso have come into play over the
years. Some level of participation of civil society and private sector actors have been
noticed with their involvement in the management process. However, the involvement of
civil society in the form of NGO participation has been more pronounced than that of the
private sector.
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The late start in the transboundary cooperation process among the riparian
governments could be partially attributed to the lack of clear institutional structures in
these countries with the clear mandate to manage water resources and pursue
transboundary cooperation agendas. With Ghana and Burkina Faso recently having
formed state institutions with the mandate to represent their countries on water
resources management issues, the stage was set for cooperation. It has also been an
important trigger for the formulation of the institutional framework for the management of
the natural resources in the Volta Basin, and greatly contributed to the formation of the
VBA. Furthermore, a normative Code of Conduct for the Sustainable and Equitable
Management of the Natural Resources of the Volta Basin has been formulated and
indications from Ghana and Burkina Faso are that it will be pursued to cover the
relationship among all the six riparian countries of the Volta Basin.
The challenges of the process, which mainly concerns the lack of governmental action
and funding, seem likely to be overcome with the formation of the VBA and the
willingness of all riparian states to come up with workable solutions for the management
of the resources of the Volta Basin. It is hoped that all the six riparian countries of the
basin will foster and expand the cooperation so far achieved to promote the sustainable
and equitable management of the natural resources of the Volta Basin.
The thesis “Paddling out of poverty. Assessment of the usage and management of
transboundary river resources for sustainable livelihood in the Bawku area” by M. Asaah
examines the usage and management of the White Volta in the Bawku area for
sustainable livelihoods. The study revealed that the riparian communities are using the
river resources for livelihood activities such as improved rainy season cropping, dry
season gardening, livestock rearing, fishing/river transportation, sand winning and brick
molding.
Table 2: Main Sources of Income of Households in selected communities along the White Volta
Community Irrigation Rainy
Season
Cult.
Livestock
Rearing
Fishing Formal
Employ-
ment
Remittance Trading
Sapeliga 70% 9% 12% 2% 1% 1% 5%
Temonde 58% 21% 10% 2% 3% 2% 4%
Mognori 62% 14% 11% 0% 4% 2% 7%
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The communities‟ engagement in these livelihood activities have improved their income
and food security. Concerns have been raised by regulatory bodies (Water resources
Commission) about the destructive (siltation, erosion etc) nature of unregulated
livelihood activities.
The study shows that traditional, customary systems and practices exist in communities
to preserve the river ecosystems. The study, however, found that these customary
practices have lost their effectiveness largely due to the introduction of modern religious
practices such as Christianity and Islam. The study also found that some governmental
organizations such as MOFA, forestry department, the district and municipal
assemblies, WRC as well as non-governmental organizations such as the GLOWA Volta
Project, PAGEV/ZOVFA/IUCN are working to assist communities to maximize their
benefit from the river in terms of livelihood and as well as preserving the river for
sustainable livelihood.
Gates and gaps in transboundary flood management. Communication structures,
networks and information flows
In the Volta Basin extreme weather events like droughts and floods pose serious
problems for the local population. Early warnings and disaster mitigation strategies
depend on well functioning communication structures and information sharing. By now
the countries of the Volta Basin are not prepared for adequate counteracting measures
as seen at the flood event in 2007.
Insufficient communication about water levels of the Bagré dam and information about
possible risks connected to spilling at the high peak of the rainy season were identified
as one major drawback to warn the population in due time. The lack of data and the
absence of efficient monitoring networks between the riparian countries (horizontal
communication) but also between the centers and the peripheral areas (vertical
communication) constitute the main gaps for successful and short term information
sharing. Even though the international Volta Basin Authority, which also aims at
facilitating transboundary cooperation in the water sector at a local level, was launched
in 2007, the coordination and exchange of the different data components (climate,
surface, groundwater) is still at its initial stage and will require a lot more institutional
capacities and concerted action at different levels to develop improved data sharing
mechanisms.
Another reason why early warnings and emergency responses could not efficiently be
applied is linked to the perceptions and attitudes of the population towards their social
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and natural environment and thus to natural hazards in general and floods in particular.
In Sapeliga, for example, a community in the Bawku West district, parts of the
population did not react to warnings which were brought to people‟s attention in time.
According to the National Disaster Management Organization (NADMO) and the Volta
River Authority (VRA) some community members who were at risk did not react to the
warnings. This “irrational” behavior was ascribed to local land rights, belief systems and
the religiously anchored function of land hosting the ancestors. In fact, land rights and
tenure regimes, different settlement patterns as well as beliefs connected to natural
resources management, all factors which are highly important for efficient flood
management, are fairly unknown at higher decision making level.
Figure 61: Map of the study area
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Gaps in flood management can finally be ascribed to contradicting national strategies
and policies in the agricultural sector. The national water policy of Ghana aims at
protecting the river banks in order to reduce problems of land degradation in an area of
increasing agricultural activities. These policies actually contradict with regional
strategies to increase food security by irrigation, which were heavily being expanded in
the recent past.
Figure 62: Communication gaps in transboundary flood management
2.5.3 Sub-project C3: Consortium Building, training and outreach in the use
of DSS
GVP partner workshops and trainings were conducted, which targeted the capacity
building of stakeholders within the Volta Basin.
Milestones achieved:
Consortium established and flourishing
Communication system put in place that allows easy exchange of ideas and
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resolution of problems
System of regular consultation put in place
Training and demonstration curricula established and tested
Methodology and Research Results
The first workshop, which was organized by UNU-INRA, was the GLOWA Volta Project
Stakeholders Workshop on "Stakeholders‟ Capacity Needs Assessment" in the Noguchi
Memorial Institute, Legon, Accra, Ghana from 31. May – 1. June 2007. About 60
stakeholders in the water sector, such as water research and development institutions,
civil society groups and water regulating bodies discussed stakeholders‟ needs in the
water sector. The topics included: climate and meteorology, water demand and
allocation; hydrology, water supply & water availability; water politics, policy, law and
supply financing. The main objective was to share GVP‟s outputs and scientific tools
with stakeholders in the Volta Basin in order to assess their needs for capacity
development. A report on the workshop is available in digital form.
From 12.-13. September 2007 UNU-INRA held a GVP Stakeholders Workshop on
"Stakeholders‟ Capacity Needs Assessment" at the Institut International d' Ingénierie, de
l' Eau et de l' Environnement (2iE) in Ouagadougou, Burkina Faso. This workshop was
organized in close consultation with the Directorate General of Water Resources
(DGRE) of the Ministry of Agriculture, and the Volta Basin Authority (VBA),
Ouagadougou. The workshop was attended by 50 participants from institutions and
organizations in the fields of water, meteorology/climatology, soils, agriculture, and
others. Topics discussed were similar to those in the Accra Workshop. A report on the
workshop is available in digital form (in French and in English).
From 26.-28. September 2007 UNU-INRA held a GVP Training Workshop on “Data
Management and Applications of GIS and Remote Sensing in Natural Resources
Management” at the Centre for African Wetlands of the University of Ghana at Legon,
Accra, Ghana. This workshop dealt with (1) meteorological, and hydrological data
collection, storage, processing and analysis, (2) techniques for dealing with missing data
presented by B. Amisigo, (3) Remote Sensing and spatial information projects in Ghana,
presented by staff of the Centre for RS and GIS (CERSGIS) of the University of Ghana
at Legon, and (4) Remote Sensing and GIS applications in the GVP, presented by T.
Landmann of the University of Würzburg and the German Space Agency (DLR),
Germany. (5) Soil Erosion Assessment was presented by B.O. Antwi. The workshop
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was attended by ca. 40 persons.
From 12.-14. December 2007, an additional workshop on data collection and RS/ GIS
was organized by UNU-INRA in Ouagadougou, and held at DGRE, Ministry of
Agriculture. This workshop dealt with (1) meteorological and hydrological data collection,
storage, processing and analysis, (2) Database management by A. Rogman (3)
techniques for dealing with missing data by B. Amisigo, (4) Remote Sensing and spatial
information projects in Burkina Faso presented by staff of the Institut Geographique du
Burkina Faso, (IGB), (5) Application of Remote Sensing for the Estimation
Evapotranspiration by H. Compaore. (6) Application of GIS Integrated Hydrology/Water
Quality Model (SWAT) for assessment of spatial distribution of water resources and
analyzing impact of different land management practices on soil erosion by D. Alamirew
and (7) Remote Sensing applications in the GVP, presented by T. Landmann of the
University of Würzburg and the German Space Agency (DLR), Germany. The workshop
was attended by 40 persons.
From 14.-17. January 2008 UNU-INRA organized a GVP Training workshop on the
“GLOWA Volta Project Hydro-meteorological decision support for the Volta Basin” in the
ISSER Building, Legon, Accra, Ghana. The workshop was attended by 19 participants
and covered the topics: i) model based water balance estimations with training in the
water balance simulation model WaSiM and climate change scenario studies; ii)
predicting the onset of the rainy season with training in specific statistical approaches,
linear discriminant analysis and linear regression analysis. The workshop was chaired
by Dr. Dilnesaw Alamirew (UNU-INRA/ GVP), and delivered by Sven Wagner and
Patrick Laux (Institute for Meteorology and Climatology IMK-IFU).
The same training workshop was held at the Direction Générale des Ressources en Eau
(DGRE) in Ouagadougou, Burkina Faso from January 22 -25 2008. It was attended by
27 participants from institutions and organizations in the fields of water and meteorology/
climatology.
From 26.-27. February 2008, GTZ, IWMI and the GLOWA Volta Project held a multi-
stakeholder workshop in Accra, Ghana on “Second Ghana Dams Forum and Workshop
on the Impact of Climate Change on the Bui Hydropower Project”. The objectives of the
workshop were the presentation of GVP research results and a multi-stakeholder
dialogue on the impact of climate change on the planned Bui Dam in Ghana. The
participating stakeholders were representatives from communities affected by dams,
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NGOs, government agencies and research institutions. Constanze Leemhuis, Wolfram
Laube and Barnabas Amisigo from the GVP chaired the workshop.
From 1.–2. April 2008 UNU-INRA organized a multi-stakeholder workshop on “Irrigation
Options in the changing environment of the White Volta” in collaboration with Water
Resources Commission (WRC) and the Ministry of Food and Agriculture (MoFA) in the
SSNIT conference room in Bolgatanga, Ghana. The main objective was to share GVP‟s
outputs and scientific tools on climate change adaptation with stakeholders in the Volta
Basin. 55 participants attended the workshop.
From 19.-23. May 2008 UNU-INRA organized a training workshop on “Introduction to
Geographic Information Systems and Remote Sensing” at the Center for Geographic
Information System and Remote Sensing, University of Ghana, Legon, Ghana.
Participants of the training workshops came from partner institutions of the GLOWA
Volta Project. Invitation letters were sent to these institutions to nominate two staff each
to be trained in GIS and RS. During the five days training workshop, the 15 participants
were taken through concepts and application of Geographic Information System and
Remote Sensing.
The last workshop which organized by UNU-INRA in 2008 was held at the Africa
Wetland Center, University of Ghana, Legon, Ghana on June 26 2008. The workshop
was on introducing MIKE BASIN / WEAP. The MIKE-BASIN and WEAP models are
used in water resources planning and management. The objective of the workshop was
to introduce participants to these water allocation and reservoir operation models. The
workshop was a combination of short lectures and demonstrations. The topics and
resource presenters were Dr. Barnabas Amisigo (Hydrologic-Economic Model
Integration for the Volta Basin), Dr W.E.I. Andah (Introduction to WEAP) and Dr. Wilson
Agyare (Introduction to MIKE-BASIN). Participants of the training workshops were from
partner institutions of the GLOWA Volta Project. Institutions in water resource
management in Ghana were invited to nominate staff to participate in the introductory
workshop. The training workshop was attended by 17.
From March 17 – 18 2009 UNU-INRA organized a training workshop on „The Use and
Application of the M3WATER Model” at the ICT Center of the University of Ghana,
Legon. During the workshop session, the participating potential user community, was
introduced to the M3 WATER Model, and engaged into discussions on policy scenarios,
climate change scenarios and trans‐boundary water allocation for the Volta Basin. They
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were also given hands‐on training on the use of the M3WATER Model. The resource
persons then discussed the possible institutional arrangement for the implementation,
data requirements, user friendliness and the available policy options and result/output
selections of the M³WATER model. The workshop was attended by 33 participants from
GLOWA Volta partner institutions from the water sector like the Volta Basin Authority,
Water Resources Commission, Hydrological Service Department, and the research
community from Water Research Institute, School of Applied and Nuclear Sciences,
University of Ghana, University of Science and Technology. Resource persons for the
workshop included Dr. Nicos Perez, Dr. Barnabas Amisigo and Dr. Anik Bhaduri, with
Dr. Wolfram Laube and Dr. Eva Youkhana as moderators
From May 12-13, 2009 UNU-INRA organized a Geoportal and Database User Workshop
on the premises of the Direction Générale des Ressources en Eau (DGRE) in
Ouagadougou, Burkina Faso. The workshop aimed at providing the participants with
knowledge and comprehension on the GVP Geoportal, how it operates and how
everyone can contribute to its functioning as well as reasons for its creation. All the 11
invited institutions and the guests have attended the workshop for a total number of 30
participants. Presentations were given by Antonio Rogmann and Peter Wittkötter from
ZEF (University of Bonn, Germany).
The last workshop which was organized by UNU-INRA in 2009 was held at Sasakawa
Centre of the University of Cape Coast from May 26–28, 2009. The topic of the
workshop was “Supporting Sustainable Land/Water-Use Management in Semi-arid
Landscapes of the Volta basin using Multi-Agent-Based Simulation”. This short training
course aimed at providing trainees with basic concepts, principal and practical steps of
multi-agent based modeling of land/water use change. Different versions of the GLOWA
Volta Land Use Dynamics Simulator (GV-LUDAS) were used as show-cases. With an
exploratory modeling strategy for complex integrated systems, researchers of the
GLOWA Volta Project at ZEF, developed GV-LUDAS to enable the assessment of
relative impacts of policy interventions by measuring the long-term landscape and
community divergences driven from the widest plausible range of options for given
policies. Thirty-one participants from various institutions in Ghana and Burkina Faso
took part in the 3–day training workshop on the use of the Multi-Agent model. The
training workshop included presentations from resources persons Dr. Quang Bao Le
and Julia Schindler of the Centre for Development Research (ZEF), University of Bonn,
Germany.
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2.6 Cluster I: GLOWA Volta Decision Support System
The cluster focuses on the development of technologies and means for integration of
distributed heterogeneous simulation systems and data sources within the decision-
making workflows. The cluster provides natural scientists and decision makers with
interactive tools for the construction and execution of decision-making workflows
enabling them also to visualize and evaluate different policy interventions.
Management of natural resources is a complex task raising questions touching many
different disciplines (biology, hydrology, etc.), which cannot be solved within a single
application. Therefore, a scientifically sound DSS to be developed in the project has to
integrate several scientific simulation systems and data sources. The integration of the
GLOWA Volta resources is complicated by the fact that data sources and simulation
systems are heterogeneous and highly distributed across institutional and national
boundaries. The straightforward solution to merge the models to one monolitic system is
not realistic because of the high complexity and heterogeneity of the models, which are
often written in different programming languages for specific operating systems that run
on special hardware platforms, such as Linux clusters or MS-Windows PCs.
Furthermore, the implementations of the models require more and more computational
power as well as data storage capacity.
One approach that promises to satisfy all these requirements is the new paradigm of
distributed computing called Grid computing. The main vision of Grid computing is to
realize a unified interface for arbitrary computational resources – including hardware,
software and data – that everybody can use without having to care about the hardware
infrastructure and the implementation details of the software components; just as easy
as getting electricity through a standardized plug from the electric power grid. While it is
unsure if this overall vision will ever be accomplished, it can be said that the Grid
computing hype is coming to maturity and that important parts of the Grid computing
technology have reached production status.
2.6.1 Sub-project I1: Requirements Engineering
In this sub-project, several open source frameworks for building grid applications were
identified and tested towards their possible implementation for the GVP DSS
infrastructure. It was decided to use the Gria 5.1 grid platform. Another subject was the
establishment of a data transformation facility within the Gria environment.
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Milestones achieved:
Completion of the elicitation and preparing the requirements specification for all
decision support questions involving socio-economic and hydrology simulation
systems (GAMS and WaSIM-ETH)
Development of the analysis model for requirements specification involving
economic and hydrology simulation systems (GAMS and WaSiM-ETH)
Milestones not achieved:
Elicitation of requirements for new decision-support questions involving climate
and land use simulation systems (MM5 and GVP-LUDAS)
Extension of the analysis model for requirements specification involving climate
and land use simulation systems (MM5 and GVP-LUDAS)
Requirements management
Requirements validation
Methodology and Research Results
In the beginning of Phase III A. Savinov focused the research activity on studying the
possibility to use the COBIDS framework as a platform for integrating various simulation
models. COBIDS is a component-based extensible platform providing interoperability via
mediators. This system makes all data commonly accessible by providing a generic and
dynamically extensible mediator framework. Mediators represent a primitive data
transformation step and they allow for exchanging structured data between any
components in the system. Taking into account these properties, its use looked very
promising in the context of the GLOWA Volta Project and the first prototype confirmed
many (but not all) expectations.
One of the primary research activities in the beginning of Phase III was studying various
existing grid computing platforms and workflow management systems that could serve
as a basis for the GLOWA Volta decision support system. More than 10 workflow
management systems including Triana, Taverna, Kepler and others have been
evaluated. One of the main requirements to such a platform is supporting the functions
of composition and execution of workflows in distributed computing environment as well
as access to intermediate results and their visualization. The goal of this research
consisted in finding a system which could serve as an alternative to COBIDS framework.
During the initial period of Phase III two grid platforms – Globus Toolkit and Unicore
have been evaluated, too. The goal was to employ grid technology in the decision
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support system which would allow us to meet many important requirements. In particular
various simulation models (such as GAMS and WaSiM) could be integrated as well as
heterogeneous data with sources both highly distributed across institutional and national
boundaries. Both of these systems provide similar functionality for virtualizing
heterogeneous distributed resources within secure environment. However, Unicore is a
vertically integrated environment while the Globus Toolkit is a set of components that
need to be configured and tuned before the system can be used.
After evaluating such platforms as Globus and Unicore 5, the testing of the new Unicore
6 grid platform started. The main distinguishing feature of Unicore 6 is that it is based on
web services and supports many gird standards. Both these factors are very important
for the project because they allow the integration of heterogeneous data sources which
are highly distributed across institutional and national boundaries.
Later however, after evaluating all the features of Unicore 6, Savinov and his group
switched to another perspective platform, GRIA 5.x, which provides similar functionality
but has better implementation and support. GRIA provides a service-oriented
infrastructure (SOI) which is designed to support collaborations through service
provision across organizational boundaries in a secure, interoperable and flexible
manner. The functionality provided by this system and possibility to use for the purposes
of the project have been studied. This system then was chosen as the basis for the
distributed infrastructure.
Another direction of research during this period consisted of developing principles and
architecture for a data transformation service which is going to be available within the
GRIA platform. The purpose of the data transformation service is to provide functionality
for integrating heterogeneous data in the grid environment. Various semantic techniques
for data annotation for intelligent data transformations have been studied; in particular
ontology-based transformations.
During this period main efforts were aimed at developing a grid-based infrastructure for
the GLOWA Volta decision support system. Here the main research efforts were aimed
at developing the technological basis for the M3WATER model which couples a GAMS-
based economic model and a hydrologic model based on the MIKE BASIN simulation
system. The following design criteria were used when developing the M3WATER model.
The user works with the coupled model using a client which provides means for
choosing various scenarios and changing model parameters. The hydrologic model run
by the MIKE BASIN system has to be executed on the server. Each simulation step
computes results for one year which are then used to generate parameters for the next
step.
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The task consisted of adapting this system to the purposes of the M3 integrated model.
In particular, it was necessary to install, configure and parameterize this system so that
it can be used by the client software. Another task consisted of adapting MIKE BASIN
for the work under GRIA. And the third task which was solved consisted of providing
data transformation procedures. The problem here is that the GAMS-based economic
model and the MIKE BASIN-based hydrologic model use different data formats and
therefore it is necessary to provide special adapters for converting and transforming
data. Essentially, these procedures make it possible for these simulation systems to
effectively cooperate within this coupling.
To meet the requirements for the GLOWA Volta decision support system, Unicore
(Uniform Interface to Computing Resources) grid platform was chosen among other
evaluated systems. It is a vertically integrated grid computing environment providing the
users a seamless, secure and intuitive access to the heterogeneous distributed
resources. In particular, it supports different hardware architecture, vendor specific OSs,
application environments, naming conventions, file systems, certificate based
authentication and administrative autonomy of participating sites. For the project it is
also important that it has an intuitive graphical user interface for creating and managing
complex interdependent jobs. After the principle decision on using Unicore as a grid
platform for the GLOWA Volta decision support system was made, they installed and
configured it for the use at the University of Bonn. Unicore consists of three major
components: Gateway, Network Job Supervisor (NJS) and Target System Interface
(TSI). In the current configuration two installations of Unicore run on two different
computers and two different configuration simulating independent organizations. By
using the Unicore client with a graphical user interface it is possible to submit jobs to this
installation.
One important feature of Unicore is that it intrinsically supports the execution of
workflows. Workflows are described in the Unicore client as dependent jobs. This
mechanism also supports some other important constructs like loops and conditional
execution. They tested the mechanism of workflows in Unicore and evaluated it against
the requirements for GLOWA Volta decision support system. For test purposes, they
developed a prototype application for creating complex interdependent jobs that can be
executed on any Unicore site without changes to the job definition. They also evaluated
the possibility to integrate COBIDS framework into Unicore grid platform so that the
necessary data transformations can be performed transparently.
Since Unicore 5 has some disadvantages they evaluated two new gird computing
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platforms: Unicore 6 and GRIA 5.x. Both these platforms are based on web services and
support main grid standards. Unicore is a vertically integrated grid computing
environment providing the users with a seamless, secure and intuitive access to the
heterogeneous distributed resources. The GRIA platform positions itself as a service-
oriented infrastructure designed to support business-to-business (B2B) collaborations
through service provision across organizational boundaries in a secure, interoperable
and flexible manner. Both platforms provide a standard client with simple user interface.
However, GRIA has also a Taverna workflow system plug-in which makes it possible to
create and manage complex interdependent jobs using an intuitive graphical user
interface of Taverna. After comparing both systems we made a principle decision on
using GRIA as a grid platform for GLOWA Volta decision support system. The system is
installed and configured at the University of Bonn. In particular, it was necessary to
configure secure access to the system by generating certificates and to configure its job
and data services.
One of the most important requirements to the GVDSS consists of having means for the
interoperability of the computational models. In particular, it is important to have facilities
for supporting automatic data transformations. It was decided to implement this
mechanism as a web service which works within the GRIA environment. In particular,
this service has to provide such functions as mediator management, execution of
transformations and knowledge base. The general design and main mechanisms of this
data transformation service were developed. The data transformation service allows the
researcher to focus on the problem domain and the tasks that need to be solved
(decision making) by reducing the efforts spent on heterogeneous data and application
integration. Their approach to this problem relies on using ontologies and semantic
annotations. Data resources, inputs and outputs of jobs will be semantically annotated
and hence made related. This knowledge makes it possible to carry out inference and
perform complex tasks in the grid environment using workflows. Thus the data
transformation service to be developed is viewed as a knowledge base that is made
available in the grid environment. Using the semantic annotations allows them to
introduce a new level of resource descriptions. Their design for the ontology-based data
transformation service is similar to that of the IRIS system. The difference is that IRIS is
intended for service interoperability while our system supports data transformations in
grid environment. Like in IRIS system, the data transformation service is based on using
mediators which are characterized using a special language like MPL (mediator profile
language). Given a registry or knowledge base with all the syntactic and semantic
information, the main task consists in finding appropriate transformations under certain
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conditions specified in the query.
The next problem that was solved is installing the MIKE BASIN simulation system and
adapting it for the use from GRIA. The idea was that this originally interactive system
could be used in a server model for executing simulation requests sent by the M3 client.
To perform this task, they developed a special adapter written in the Python
programming language and actively interacting with the Windows COM object
representing MIKE BASIN using special API. This adapter is an integral part of GRIA
where it is responsible for starting MIKE BASIN jobs using parameters received from the
client. One important task of this module consists in converting data between formats of
GAMS and MIKE BASIN simulation systems. In particular, input data received in GAMS
format have to be converted to MIKE BASIN and after simulation the results from MIKE
BASIN have to be converted to GAMS format.
One of the most important final results of Phase III is the M3WATER model. This
integrated simulation system consists of one server where MIKE BASIN runs under
GRIA and an interactive client where the user can choose various simulation parameters
and scenarios. We also integrated a WEAP hydrology simulation system prototype into
the M3 model where it can replace the MIKE BASIN system.
The research work of Y. Leng was to design a system architecture and to test various
existing technologies to reduce heterogeneities when integrating with data intensive
applications. After evaluating the use cases of the GLOWA Volta Project and existing
approaches of data integration, she and her colleagues found that building the scientific
workflow is the best way to simplify the process of integration process. However, those
updated technologies do not satisfy our needs as they require hard to capture semantic
information and lack the capability to transform data from one scheme to another. The
development of a new integration system itself was found to be unnecessary.
A three layered system was defined: workflow composition layer, mapping layer, semi-
concrete workflow generated layer, workflow execution layer. Her task focused on the
first three layers (Figure 63). Firstly, the simulation systems are wrapped with SAWSDL
(Semantic Annotations for Web Service Definition Language) which is used to capture
semantic knowledge of the underlying simulation systems and then in the mapping
layer, the heterogeneities will be recognized with the help of ontologies. In the third
layer, the correspondent mediators will be generated to do the data transformation. The
“best source of irrigation water” was chosen as a typical use case. OGSA-DAI (Open
Grid Services Architecture Data Access and Integration) data services are built to fetch
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the result data from GAMS and WaSiM. Taverna, a workflow management system is
used to generate the integration workflow. OGSA-DAI plug-ins are developed to
integrate OGSA-DAI services into Taverna workbench as workflow components. On the
other hand, domain ontologies, like hydrological ontology and some high-level
ontologies, such as the “Measure Unit” ontology are defined for the project using
Protégé application. The next step is to build a data transformation component using
OGSA-DAI components with the help of ontologies.
Scientific workflows have been introduced in the GLOWA Volta Project (1) in order to
help the project‟s researchers in the decision-making process through orchestrating
and integrating several involved simulation models and heterogeneous data sources.
Much research has already been done to provide efficient scientific workflow
management systems (WFMS). However, most of such WFMS are coordinating and
executing workflows in a centralized fashion. This creates a single point of failure,
forms a scalability bottleneck, and often leads to excessive traffic routed back to the
coordinator. Additionally, none of the available WFMS provides means for dynamic
data transformation between services in order to overcome the data heterogeneity
problem. M. El-Gayyar’s research work is intended to design a new approach for
scientific workflow management targeted to provide ways for an efficient distributed
execution of data-intensive scientific workflows.
The first step in his research was to determine a set of functional and non-functional
requirements of the expected WFMS according to the requirements formulated in
subproject I1. The most important requirements of the system were the following:
Support for distributed management and execution of scientific workflows.
Full control over long-running processes.
Dynamic data transformation in order to support integration of
heterogeneous applications.
Diminution of communication traffic between cooperating services.
Support for smart-rerun where only minimal set of services need to be re-
executed.
Help user to monitor and steer workflows.
Then he has explored existing WFMS and identified its main characteristics,
advantages and weaknesses. A practical evaluation of the most potentially suitable
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WFMSs showed that each of them still lacks some key features necessary to fulfill the
project‟s needs (2). According to this comparison, he has developed a new approach
for scientific workflow management. Figure 63 shows the presented approach. It has
introduced a four-layered architecture for a WFMS supporting integration of
heterogeneous data-intensive applications:
Workflow Composition Layer: This layer helps project researchers to create
semantically annotated abstract workflows. For every service, users can specify
a set of resource requirements (e.g. OS, CPU speed...etc). The task‟s resource
requirements are used during the execution phase in order to determine the
most appropriate resource for the task execution. Annotations in the abstract
workflow provide references to a set of ontologies. Ontologies are required in
the next two layers to generate mediators necessary for data transformations
between heterogeneous applications.
Mapping Layer: This layer contains three main components: First, the semantic
matching component which enables two types of matchmaking: semantic
matching and manual matching. Semantic matching aims to find corresponding
pairs between ontologies. Manual matching supplements the semantic matching
and allows users to validate semantic matching results and define additional
case-specific correspondences. Second, the mapping component which intends
to create a set of mapping expressions according to the correspondences
obtained from the matching layer. Mapping expressions are a series of
transformations needed to solve data heterogeneities. Finally, the mediator
generator component which exploits mapping expressions to create data
transformation mediators. Then, it indexes these mediators in the mediator
catalog and embeds their references in the abstract workflow.
Semi-Concrete Workflow Generation Layer: This layer is responsible to
generate semi-concrete workflows. The term”semi-concrete” here means that the
workflow still lacks information about which concrete computational resources
will be used. This information can be obtained later in run-time. This decision is
taken due to the dynamic nature of grid environments. Thereby, the early
allocation of resources for long-running processes could become obsolete. Semi-
concrete workflows combine descriptions of abstract workflows and resource
requirements obtained from the workflow composition layer with mediators
information retrieved from the mapping layer.
Workflow (Wf) Execution Layer: This layer is responsible for executing and
monitoring the semi-concrete workflow over a set of distributed resources.
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Figure 63: Architecture for WFMS in the GLOWA Volta Project
El Gayyar‟s research work focused on the Workflow Execution Layer which employs
Web Services technology to originate a new distributed execution paradigm for data-
intensive scientific workflows. The salient features of such execution mechanism
include: i) support for distributed execution of workflows, ii) reduction of communication
traffic through reference-based data movement, iii) full control over long-running
applications, iv) dynamic data transformation via generated mediators, v) support for
Semantic Matching
Service
Catalog
Semi-Concrete WF
Workflow Cases
Domain
Ontology
Matching
Ontology
Functional
Ontology
Semantic MappingRules
Ontology
Mediator Generation
Generate Abstract WF
WF Design Tool
Mediator
Catalog
Mapping
layer
Wf Composition
Layer
Semi-Concrete Wf
Gen. Layer
Wf Execution
Layer
Workflow Execution Service
Scheduler
Service
Data Mgt.
Service
Task
ServiceNode Info.
Workflow Execution Service
Simulation Service
GAMS
Workflow Execution Service
Simulation Service
WASIM
Scheduler
Service
Data Mgt.
Service
Task
Service
Node
Info.Scheduler
Service
Data Mgt.
Service
Task
Service
Node
Info.
Concrete
Wf
Resource
Requirements
Mediators
Information
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smart re-run through data caching, and vi) distributed fault handling and load balancing.
The Workflow Execution Layer in Figure 63 provides a new approach for the distributed
execution of semi-concrete workflows. The basic idea of this approach is to separate
workflow control and execution flows. It can be realized as a deployment of a bundle of
Web Services Distributed Management (WSDM) (3) services for workflow management
in every Grid node. This bundle consists of four manageable resources which need to
be deployed in every Grid node. The functionality of each of these resources is
described in the following subsections.
The Node Information WS-Resource provides the capability to retrieve information
about Grid nodes involving both relatively static information (such as system
configuration) and more dynamic information (such as instantaneous load). Such
service can be used by the scheduler resource in order to find the best Grid node to
execute a given task according to the task-specific requirements. In case the current
state of all available resources is not satisfying the task‟s requirements, the scheduler
subscribes itself to the Node Information service in all available Grid nodes. Whenever
a Grid node updated state satisfies a task‟s particular requirements, its Node
Information service notifies the subscribed scheduler. The Node Information service is
also responsible for updating the Service Catalog. Once a service is deployed /
undeployed on the underlying node, the service sends a notification to the Service
Catalog in order to update its services table.
The Data Management WS-Resource is dedicated to reference-based data movement
between nodes and automatic data transformation between heterogeneous services.
The Data Management service is based on the OGSA-DAI (4), an open source
middleware which connects data resources to the Grid environment. The main reason
behind selecting the OGSA-DAI framework is that data transformation mediators, which
are built in our workflow management system, are just OGSA-DAI workflows that
combine several atomic data transformation activities in order to transform the data
formats from one service to another. In our execution paradigm, the output of a
workflow‟s task is stored in an eXist-db, an open source database management system
entirely built on XML technology. The OGSA-DAI wraps the XML database and
provides external access to it as a web service. Data movements are done through
OGSA-DAI references in the format
“ogsadai_service_url@collection_name:document_id” which consists of three parts:
the first part is the URL of the OGSA-DAI service; the second part is the collection
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name in the XML database while the third part is the identifier of the required document.
A new Scheduler WS-Resource (workflow’s main scheduler) will be created every time
a user submits a workflow for execution. The scheduler coordinates and monitors the
overall execution of a workflow instance. To achieve this, it provides the following
capabilities:
Workflow partitioning: The scheduler tries to break a submitted semi-concrete
workflow into subworkflows. The scientific data model of our system is just an extension
of the XScufl - the workflow description language used in Taverna (5). Such extension
has been made in order to support loops, allow users to specify minimal resource (Grid
node) specifications required for the underlying service execution, and to allow data
handling through OGSA-DAI references. The main partitioning criterion here is that
every subworkflow has only one remote task/processor (e.g. web services or Grid
services). Each subworkflow will be submitted to an execution service located on the
same Grid node where the remote service is located. Accordingly, the execution service
will have a full control over the service execution. Additionally, the scheduler constructs
a dependency table which determines the data and control dependencies between
subworkflows. An example of a partitioned workflow is shown in Figure 64.
Figure 64: Example of Workflow Partitioning
Just-in-time planning: Grids are very dynamic environments where the availability of
resources and their load state can vary from one moment to another. Therefore, the
scheduler utilizes a just-in-time planning to schedule the execution of subworkflows.
First, it determines which sub-workflows are ready for execution according to its
dependency table. Then, it contacts the Service Catalog to retrieve a list of currently
MM5
Climate - 1 weekLand Use Data
WaSiM
Hydro - 1 hour
GAMS
Economy - 1 min
Out_1 Out_2
Out_3
Out_1 Out_2
WF_Output
Out_3
WF_Output
MM5 Land Use Data
WaSiMGAMS
swf_1 swf_2
swf_3 swf_4
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available Grid nodes for each remote task (Web/Grid service). In case that there are
more than one resource satisfying the task‟s requirements, the scheduler gives a higher
priority to the Grid resource where the task‟s input data is located, if such a node exists
in the retrieved list. Otherwise, it selects the best satisfying resource.
Monitoring the execution of subworkflows: For every sub-workflow, the scheduler
creates a new Task WSResource on the Grid node, selected during the planning phase,
and submits the sub-workflow for execution. The scheduler also subscribes itself to the
execution state events produced by the Task service. Once the scheduler receives an
“execution completed” event, it extracts the sub-workflow‟s output OGSA-DAI
references from the event, updates the dependent sub-workflows‟ inputs with these
references, updates the dependency table by removing all dependencies forced by this
subworkflow, and starts a new planning phase for sub-workflows not yet executed.
Fault Handling: In the event that the scheduler does not have any execution event
from a monitored Task service after a fixed time-out, the scheduler first tries to request
a progress report from this service. The lack of response means that there is a problem
either with the Grid node itself or with its deployed Task service. Such a problem can be
solved by rescheduling this sub-workflow on a different Grid node. Moreover, the
scheduler notifies the Service Catalog about the new node status. Hence, the Service
Catalog updates its services‟ table in order to prevent other partners from selecting the
broken node in the future.
Check pointing: After the execution of each sub-workflow, the scheduler stores a
snapshot of the current execution state. These snapshots can be used later on to
resume a computation in case of failure. Such a feature is very important, especially in
our case where workflows contain several long running tasks (e.g. simulation systems).
A new Task WS-Resource will be created by the main scheduler for every sub-
workflow that needs to be executed. The Task service is responsible for the actual
execution of the submitted sub-workflow. Our workflow specification language is based
on the XScufl, whereas the core of the Task service is based on the freefluo engine6
which is the Taverna‟s workflow enactor. In order to execute a submitted workflow, the
Task service follows the following sequence:
Input preparation: For every input found in the workflow description, the Task service
creates a new thread which performs the following steps in order to retrieve the
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required input:
1. If the workflow description indicates that a mediator is needed to transform the
input data to the format of the underlying service, the thread contacts the
Mediator Catalog and retrieves the indicated mediator which is represented as
an OGSA-DAI workflow.
2. Constructs an OGSA-DAI workflow which should be submitted to the Data
Management service located on the source node in order to apply the required
transformation and to retrieve the transformed data.
Execution of the workflow: The Task service waits until all threads are completed,
prepares an input list and starts the workflow execution. Before the execution of the
underlying service (e.g. a simulation service) is started, the Task service first checks
whether a cached output for its given input is available. This feature helps to achieve
smart re-run, since scientists generally tend to change few parameters of their model
and re-execute their workflows. In this case, only those services with modified
parameters will be re-executed. The user is able to force the system to re-execute a
service even if a cached output for its given input exists.
Output caching: The Task service asks the local Data Management service to store
the workflow‟s output. The Data Management service saves the output of the underlying
service and maps it to the MD5 fingerprint of the given input. Then, it stores the final
workflow outputs and generates their OGSA-DAI references.
Notifying the scheduler: Finally, the Task service notifies the main scheduler by
sending an “execution completed” event, containing the output references.
During the workflow execution, the Task service gathers provenance information. In the
future, we will record this information in a data catalog. Moreover, the Task service
provides distributed fault handling and load balancing mechanisms. For instance, if
the underlying service is broken or the Grid node is heavily loaded, the Task service
can create a local scheduler instance in order to find a new Grid node whereto the
subworkflow could be transferred. Then, it notifies the main scheduler about the newly
selected Grid node so that it can subscribe itself to the sub-workflow‟s execution events.
In case of a broken service, the Task service also notifies the Service Catalog about the
new service status. Hence, the Service Catalog updates its services‟ table and sends a
notification to the Grid administrator in order to report a failure. In order to illustrate how
services on different nodes collaborate together, Figure 65 shows a sequence diagram
for an execution scenario of a single sub-workflow. In this scenario, the input required
by the workflow is located in Node1.
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NIS@Node2MS
TS@Node2
getcurrentstate()
Service Catalog
List(swf_1)
Mediator Catalog
submit(swf_1)getmediator(mediatorID)
DMS@Nod2
getinput()
DMS@Node1
transformData()
executeSubWorkflow()
cacheOutput()
OutputReferences
[Node2]
Memory, disk space, ...etc.
Mediator Workflow
Transformed Data
executionCompleted(outputReferences)
MS: Main Scheduler NIS: Node Information Service
TS: Task Service DMS: Data Management Service
Figure 65: Workflow Execution Sequence Diagram
2.6.2 Sub-project I2: GVDSS Infrastructure
This sub-project developed data management standards and rules of access for the
GVP Geoportal to improve data quality and security. The demand and needs of local
stakeholders were integrated in the definition of rules and data management standards
were defined. Other colleagues continued with the development of the DSS tool. The
MIKE BASIN water resources network model serves as a powerful platform to integrate
the simulated modeling results of the coupled atmospheric-hydrological model MM5/
WaSiM and the economic MATA/ M3 WATER model.
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Milestones achieved:
Design of the architecture of the GVDSS Grid infrastructure
Evaluation of existing software frameworks facilitating the realization of the “low-
level”, core functionality for the Grid infrastructure
Evaluation of existing workflow management systems facilitating distributed
workflow execution
Adaptation of the selected workflow management system to the Grid
infrastructure and integration with the COBIDS data transformation facilities
Development of the specific local services (LS) enabling access to the Grid
infrastructure and solving the time-scale problems for GLOWA Volta data sources
and simulation services
Preparation of the required distributed computing environment, IT consulting and
advisory services to the KACE, and the UNU in Accra
Milestones achieved with deviations:
Test and evaluation of the DSS infrastructure on the most common decision-
making scenarios
Instead of the COBIDS mediator framework, the GRIA platform was used.
Transfer of the DSS to Ghana, installation and validation of the DSS functionality
Individual components were transferred to Ghanaian and Burkinabe stakeholders.
The Geoportal could only be transferred in a preliminary version due to technical
restrictions.
Adaptation of the COBIDS mediator framework to the Grid infrastructure and
implementation of global core Grid services (Mediator Service, Catalog Service)
on top of the selected software framework
The adaption of the COBIDS mediator framework was not pursued as initially
planned because the original design idea proved not to be effective. Instead,
newly designed catalogues were developed (Service, Mediator, Workflow) and
integrated into the system.
Methodology and Research Results
Based on a detailed analysis of the deficits and shortcomings of the projects data
infrastructure in summer 2006 by A. Rogmann, major improvements were proposed. He
identified the need to reorganize the database architecture because of complicated
access to the existing databases and a lack of suitable tools to search and evaluate
data. It was recommended to develop a web-based data infrastructure to provide
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efficient remote access to the GLOWA Volta data stock through a catalog-service in
combination with portal- and portrayal-services for geospatial and non-geospatial data
and data products.
Based on the expertise and a user requirements analysis, the basic concept for the data
information system (called GVP-Geoportal) was developed in close collaboration with
the computer scientists S. Shumilov and J. Laubach (Cluster I, Dept. for Computer
Science III, Univ. of Bonn). It entailed a technical concept for database access (data and
metadata) using web-services (catalogue service, data download service, and map
service). The component-based architecture that was developed ensures reliability,
flexibility and scalability of the GVP Geoportal. Data and their ownership rights need to
be protected by a multi-level user management, and data security is provided by
technological measures like the separation of the main access components of the
system (web server / data server).
User requirements were analyzed in order to design a map server web-interface for
visualization and assessment of geospatial data as part of an optimized data
infrastructure. Additionally the reorganization of the data storage structure according to
scientific disciplines on the project data server was undertaken in autumn 2006 to
improve data exchange between the project members through the Local Area Network
until the Geoportal was launched. Based on the concepts developed in 2006/2007, J.
Laubach started with the programming of the core components of the GVP-Geoportal.
Because a technical solution for data management has to be embedded into a data
policy a project-internal manual on data management was written addressing such
aspects as data naming, exchange formats, data quality, metadata, and the storage
structure on the server.
The integration of geospatial data, at that time mainly stored as vector shapes and
raster files, into a relational geodatabase accessible by the Geoportal was promoted by
a geodatabase workshop for senior scientists and interested students. The participants
were trained in using relational geodatabases by subsequent exercises. The workshop
provided the participants with an overview on the advantages of this special type of
geodata storage
A survey addressing data management issues (GVP Data Questionnaire) was carried
out together with stakeholders and project partners working on water management in
Ghana. The results were used to adjust the data management framework of the
GLOWA Volta Project to the stakeholder requirements (Capacity Needs Assessment
Seminar, Accra, Ghana, June 1st, 2007).
In autumn of 2007 the model for the GVP Geoportal was partially modified, considering
the results of the data questionnaire. The new web-based data infrastructure, consisting
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mainly of data server, Geoportal, map server and -client with corresponding interfaces
(Figure 66) was presented and discussed with project partners in Ouagadougou at the
“Data management and Application of GIS and Remote Sensing in Natural Resources
Management Training Workshop” on December 14, 2007.
Figure 66: Architecture of the GLOWA Volta Geoportal
A survey similar to the one conducted in Accra in June 2007 was repeated in this
workshop. The results of these surveys (Figure 67 and Figure 68; report published in
2008) show, that in the Volta Basin no structured data management environment
existed. The main problem in handling data is to get adequate information (metadata)
about data. Provider, content and quality of data are often unknown.
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Figure 67: Votes by 19 members of institutions from the Ghanaian water sector concerning problems with
information about data
Figure 68: Votes by 13 members of institutions from the Burkinabe water sector concerning problems with
data transfer
The main conclusions that were stated are that a web-based application for data
management is strongly needed. It should be based on free software to avoid costs,
provide high performance services with small rates of data transfer (which is important
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when using slower internet connections), protect ownership rights, and offer intuitive and
easy to use interfaces to help data user and data provider to share data.
In May 2008 the first version of the Geoportal was launched as a proof-of-concept for
the proposed data information system in the GVP. After the launch of the prototype, it
was filled with content and the usefulness of its functionalities were closely examined by
the data management department at ZEF.
The development and programming of the Geoportal prototype by J. Laubach and S.
Shumilov was evaluated through a survey made with 13 German GVP project members
(from senior fellows to PhD students) This questionnaire asked for the acceptance of
features provided by the Geoportal prototype (Figure 69) and requested suggestions for
its improvement. While most participants stated that the functionality provided satisfy
their requirements, a few recommendations were made. Several questions were asked
regarding search functions, up- and downloading of data and metadata, and the
visualization of geodata via web-map-services (WMS). The results were used in the
diploma thesis of J. Laubach, and for the improvement and extension of the portal‟s
functionality. Keyword-lists, a comprehensive metadata editing guide, data categories
with preselected data sets linked with metadatabase queries, and thematic maps were
included in the Geoportal. In June 2008, the main phase of data ingestion was started.
Data was entered by scientists, project members, and the data management
department, using a data management workflow that was defined to facilitate the
preparation and integration of data into the system.
For the GLOWA Volta status conference demo-scenarios for the Geoportal were
developed to illustrate the flexibility and simplicity of the system in terms of data
description and distribution. In close co-operation with the senior fellows and their
assistants the second part of the year was intensively used to insert metadata, data and
maps into the GVP data infrastructure using the Geoportal web interface.
In order to improve the understanding of the requirements to sufficiently meet data
standards, the data management manual written in 2007 was updated and illustrated
with a graphical scheme of the data management workflow (Figure 69).
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Figure 69: The data management workflow
In order to prepare the transfer of GVP Geoportal and databases to the project partners
in the Volta Basin, A. Rogmann and S. Shumilov delivered a two-day Geoportal User
Workshop (Accra, November 26-27 2008) to governmental actors and scientists from
the Ghanaian water sector. The main goal was to present the Geoportal to a wider
potential user community, to make the participants familiar with the Geoportal, and to
explore further demands on the system. The participants worked through exercises, e.g.
dealing with setting access restrictions to institutional data stocks. In particularly, the
aspects of owner rights, process status and exchange demands were addressed. At the
end of the workshop, the demand for an improved data infrastructure such as provided
with the Geoportal was broadly stated by the participants and most of the participants
declared their interest and willingness to actively contribute data and metadata to the
Geoportal. However, in some cases the decision to contribute to the Geoportal has to be
taken by the authorities.
The main part of the activities in 2009 was dedicated to including data and web-services
into the GVP data information system and to prepare the system for transfer to the Volta
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Basin Authority in Ouagadougou, which will act as host for the Geoportal and its
databases.
The programming of an offline tool (GVP-Geoportal Offline Tool, Figure 71) to manage
local metadata (without connection to the Geoportal databases), which has been started
in 2008, was finished by P. Wittkötter and implemented as a module in the Geoportal
framework. It allows users to generate metadata offline, e.g. when working in the field.
After connecting to the internet, a metadata harvester facilitates the sampling of all
entered metadata files (xml) on the local drives and the successive upload to the main
metadatabase of the Geoportal. With this offline tool, Geoportal users are encouraged to
prepare data for the Geoportal independent of internet access.
Figure 70: The GVP-Geoportal Offline Tool for editing metadata in the field without connection to the
internet. Image shows the interface to generate the Uniform Resource Name (URN) for a metadata set
In May 12-13, 2009 the second part of the “Geoportal and Database User Workshop” for
the francophone stakeholders took place in Ouagadougou. The workshop aimed at
explaining the use and the administration of the Geoportal reflecting data management
policy in order to motivate stakeholders to share water management related data. As a
result from exercises on metadata management, the participants‟ awareness and
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understanding of the advantages provided by the Geoportal framework was raised.
In May 2009, the Geoportal and its databases was installed at the Volta Basin Authority
as an offline version (only accessible within the VBA intranet) to be used and tested in
practice. The evaluations will be used in the GVP implementation phase to customize
the system to the requirements of the VBA and to integrate the Geoportal in a proposed
VBA website.
Based on an intensive communication between the metadata providers (scientists,
assistants) and the data management department, many small improvements were
made to the Geoportal during the last months of the project. By the end of the project,
more than 370 metadata sets and more than 60 different maps (Figure 72) composed of
single or combinations of several map layers (as WMS) have been integrated (maps by
P. Wittkötter) and are now accessible for project members as well as for the public.
Ownership on data is protected by the user rights management of the Geoportal.
The Geoportal can be accessed through http://131.220.109.6/Geoportal/. Although
public access is available only since May 2008, we have already received and served a
large number of data requests by both African and international students, scientists and
practitioners.
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Figure 71: Page of the GVP-Geoportal displaying links to interactive project maps
2.6.3 Sub-project I3: GVDSS Workbench
This sub-project developed the Advanced Visualization Framework, which will allow
future users to import and compute data interactively in the form of diagrams or charts.
Milestones achieved:
Analysis of existing graph-based workflow composition systems and adaptation of
the selected system to the GVDSS infrastructure and client
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Building a collection of workflows according to the set of use-cases defined in
subproject I1
Integration of existing GIS-like visualization and analysis facilities for multi-
disciplinary data with the GVDSS client
Milestones achieved with deviations:
Implementation of the common GVDSS user-interface for stakeholders and scientists
The modular decision support tool approach required custom designed user
interfaces
Testing, validation and finalizing of the GVDSS client
The modular decision support tool approach is not built on a single GVDSS client.
The individual components were tested and validated.
Methodology and Research Results
The main goal of the I3 sub-project is the development of the analytical workbench as a
part of the GLOWA Volta Decision Support System. It should allow several groups of
users with different level of expertise to configure and run simulation models, analyze
relevant data, and browse interactive reports about the results of analysis, as well as
exchange ideas and suggestions among fellow users.
For the most effective implementation of the software products, the development
activities should follow the use cases, defined in close discussions with domain experts
and future users of the system. Together with other members of his group in the
Computer Science Department, I. Denisovich extended the existing descriptions of
previously defined use cases and produced further use case descriptions based on
brainstormings with other project members.
To allow visual exploration and analysis of spatial and temporal project data, he
developed the Analytical Visualization Framework. As many of the well-known
visualization techniques are available in open-source and commercial software libraries,
he evaluated their applicability to project data and software environment. The selected
candidates provided the basis for the prototype implementation of the framework.
In addition to the existing components, he developed the workspace for graphical
definition of data transformation for further visualization, aggregation of information from
various sources, and design of multiple coordinated data views. Independent modules
can be combined to define the transformation steps; the user can combine these
modules in runtime using the graphical editor, which enables the interactive exploration
of data. Using services provided by the Analytical Visualization Framework, users can
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import data relevant to the project, make interactive computations and represent the
results in form of diagrams, maps or charts. The framework is based on modular
architecture. Each module performs an atomic transformation of data. Complex
transformations are performed by chained modules. The modules can be connected in a
visual programming workspace. The framework adapts to changes and re-computes the
transformation only in the changed part, taking already computed data where possible.
Such a method uses computing resources most effectively and makes interactive
computation possible. The user can, for instance, change parameter with a slider and
immediately see the changes reflected on a thematic map. The important feature of the
Analytical Visualization Framework is the possibility to interact with data by manipulation
of its visual representation. To do so, the user can draw on a visual display with a
mouse pointer or a tablet pen. One can, for example, encircle a cluster of points on a
map or draw a line separating regions. By doing so, the user introduces regions in the
display space populated by visual representations of currently displayed data elements.
For example, an encircled region classifies all displayed elements into two parts: inside
and outside the encircled region. Thus, the user can rapidly make complex selections of
data elements, apply transformations or compare statistics of selected data to the
statistics of the whole dataset.
One of the major collaborative achievements in the GLOWA Volta Project is the co-
development of the hydro-economical model M³WATER for the whole Volta Basin.
I. Denisovich’s role in this activity was the development of the graphical user interface
that allows users to simulate complex scenarios without any background knowledge of
the models running in the background. All important model parameters can be entered
through convenient dialogs. After that, the user simply presses a button to start the
integrated simulation, and after it is finished, can browse and analyze the results in a
specially designed visualization interface. This data presentation interface was
developed using the Analytical Visualization Framework introduced earlier. The
framework itself was greatly improved and adapted to provide functions needed for the
effective representation of the model output. Its modules for data transformation and
aggregation were also used to collect data produced by the hydrological and economical
sub-models during their runs. The framework was also extended to support the
execution of remote tasks in grid infrastructure based on GRIA system. As easily as
building local data transformations with traditional AVF modules, the user can now
attach grid jobs running on remote machines. New modules provide services to explore
available grid services, submit grid jobs, and transfer of data between local client and
remote grid node, as well as directly between grid nodes.
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Although the model infrastructure can be installed on a regular PC, the licensing issues
for several components and the volume of the installation package restrict the
community of users that may run the model on their computers. Instead of installing the
whole infrastructure on each client computer, it is easier to set up a powerful server with
enough resources to host the model and serve many clients accessing it through
internet. The users can prepare a list of scenarios they want to compare and run them
all in queue. Moreover, the users are not required to wait for the model to finish
simulation, but can return to the site later to see the results of the execution.
To adapt to different applications and to address the various needs of the users of the
decision support system, the flexible modular architecture has been developed. Tasks of
data access, processing, interactive manipulation and visual analysis are divided into
atomic data transformation operations. These operations can be either implemented
using conventional programming language, or composed from other modules. The
programming interfaces and base library for the development of modules are provided in
Java programming language. Most of the technical issues, like the connection of inputs
to outputs of modules, or notification of all connected data consumer modules about the
new data available from the corresponding data supplier module, are implemented in the
base library for all modules, so that the programmer can focus on development of the
main functionality of the transformation.
Based on the needs of the project and gathered use cases, he developed the essential
modules for reading common raster and vector data formats, transformation of the
source data into visual form, representation and manipulation on visual displays. New
modules, both Java-based and composed from the other modules are continuously
added to the library to support more visualizations and required transformations.
For easy interactive composition of data transformations and development of advanced
visualization tools, he developed the visual graph editor. The user can place the
modules into its workspace, connect corresponding inputs and outputs of the loaded
modules, check the transformed data at each step, direct the data through various
transformation paths, alter the parameters of that transformation with interactive controls
and directly see the changing visualizations.
The results of analysis, as well as the steps the analyst made to acquire them, should
be documented. He developed the tools that allow the user to preserve the expressive
visualizations together with the data transformations and visual tools used to produce it.
Besides storing, the user can add notes and explanations and annotate the data
representation with freehand drawings on top of the display. Such annotations ease the
collaboration between scientists and allow forming of advanced data queries with easy
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and natural procedure. The implementation of the Analytical Visualization Framework
prototyped in the beginning of the Phase III of the project has been continuously
improved in both stability and functions. The users can now rapidly create complex data
transformations by dragging required modules from the module palette, dropping them
into the workspace and connecting inputs and outputs of modules with the mouse. The
graphs of elementary modules connected together act themselves as higher-level
modules. Such structures can be used for other computations, applied to other data,
saved and shared among users. Each module receives its input data from other
modules. The original data for the transformation is either imported by a reader module
or provided by a property module. Each property module keeps a single value, which
can be queried or changed by connected modules.
Vector-based geographical data is handled by table-processing modules. Each
geographic feature is represented as a record in a table. The attributes of such table
include one or several shapes encoding spatial information of features and various
quantitative or qualitative attributes that store thematic information. New attributes can
be computed by a special module from existing attributes by a chain of transformation
modules. This chain is applied by the attribute computation module to each feature in
the table. The attribute computation module takes values of existing attributes, supplies
them to the transformation chain and takes the results of computation as the values of
the new attributes.
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Figure 72: Example visualization of poverty statistics for districts in Ghana constructed from transformation
modules using the Analytical Visualization Framework. Colored map, table view and value distribution
histogram provide different perspectives on the same data
During visual data analysis an analyst continuously applies different methods to various
portions and attributes of data. When the produced visualization reveals some important
characteristics of the data, the analyst may want to preserve this visualization together
with description of the data and applied methods, supply it with personal comments and
annotations. The user can preserve the current structure of interconnected modules at
any time with a simple action. Each preserved state is displayed as a node in an
automatically constructed graph of analysis.
The framework plays an essential role in combining components of the M³WATER
model. It connects hydrological model in MIKE BASIN with economical model in GAMS.
The simulation is done in one year cycles. Yearly water demand provided by GAMS
needs to be transferred into MIKE BASIN, which, in turn, generates yearly water supply
needed by GAMS. Models exchange data until they agree on water balance. After that,
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simulation proceeds to the next year. The automation of model execution is done by the
M³WATER client. It is responsible for providing models with input data, running them,
getting simulation results, adapting data to be passed to another model, as well as
collecting and aggregating yearly results for the common output of the simulation. The
hydrological model needs rainfall data for the period of simulation. The user can classify
each year of the simulation into five categories as very wet, wet, regular, dry or very dry.
Based on this selection, the client takes the real rainfall data of a characteristic year
from the past and feeds this data to the hydrological model. After the simulation is
finished, the graphical analysis tool based on AVF is started, where the user can browse
aggregated results in form of tables and diagrams.
Figure 73: The main workspace of the Analytical Visualization Framework: Digital elevation model of the
Volta Basin at 1km x 1 km resolution. Visualization is constructed by the design shown on Figure 72. It
consists of a map display and a slider for interactive changes in color scale
At the end of the project, I. Denisovich focused on developing the web interface for the
M³WATER model. It is deployed as a servlet incorporating business logic, web forms,
generators for dynamic pages, and renderers for graphical presentation of simulation
results. The specifications of the scenarios are stored in a database. The Ajax
technology is used for communication between client browser and server, which
ensures, that client will get the notifications from the server when the simulation is
completed and the user can request the results. The servlet also uses the modules of
Analytical Visualization Framework to produce graphs for the results page.
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3. Summary and Conclusion
With the conclusion of the third phase, the nine year research effort of the GLOWA Volta
Project was brought to a successful end. The detailed evaluation of the performance
and achievements relative to objectives and projected milestones can be derived from
the summaries of the individual research activities presented in the previous chapters.
This section contains a more general critique of progress toward stated goals.
Overall, the integration of Phase I and II research results, knowledge, data and tools in
the third phase was successful, in that numerous research works and tools built on the
research results and expertise obtained in the first two phases of the project. As it is
documented in the previous chapters, numerous Ph.D. students have based their work
on, or included, data sets and research infrastructure that were produced or set-up in
the earlier project stages. The greatest degree of integration of Phase I and II products
was achieved in the coupled hydro-economic optimization tool M³WATER, which makes
use of the joint hydro-meteorological model MM5-WaSiM, introduced a water resources
model (Mike Basin) and an economic model which was fed with variables collected in
the previous project phases. The model components were then integrated through a
GRIA grid computing infrastructure that was developed for this purpose, building on the
experience made in Phase II with COBIDS (Component-based integration of data &
services). Besides the integration aspects the M³WATER model combines, it also
provides the framework to evaluate and project the effective demand for water
resources as a function of growing demand (population growth, expansion of agriculture,
demand for hydropower, etc.) and changes in water availability as induced through
global environmental change.
The development of operational research models and tools has been largely on track
throughout the third phase of the project. A range of scale and scope specific tools and
models have been developed (Figure 2) which are described in detail in the previous
chapter. During the International Conference on “Global Change and Water Resources
in West Africa” (August 2008 in Ouagadougou, Burkina Faso), these operational models
were presented to stakeholders and participants as the components of the GLOWA
Volta Decision Support Tools, and brought to our counterparts in a dedicated series of
workshops and trainings.
The success of the project can be shown in different ways; in terms of direct research
results, by comparison with the time prior to the GLOWA Volta Project, and regarding
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the legacy it leaves behind for the future. The direct research results have been
discussed thoroughly in this report, and the extensive list of peer-reviewed publications,
the doctoral theses, and the numerous contributions to conferences give a detailed
account of the cutting-edge research that was conducted in the often data- and
infrastructure- constrained setting of the Volta Basin.
In comparison with the situation in the Volta Basin prior to the GLOWA Volta Project we
can conclude that a number of key problems have been addressed successfully. The
effects of global environmental change and population growth on the hydrological cycle
are now understood and a variety of decision support tools are now available, which was
not the case prior to the project. The GVP has also fostered interdisciplinary work, both
in the project itself and with its project partners, and replaced the non-integrated, mono-
disciplinary approach commonly used. The problem of scattered data and data scarcity
has improved significantly with the development of the Geodatabase and the launch of
the Geoportal. Furthermore, the limited human and institutional capacity has been
effectively advanced, through the development of human capital, infrastructural and
technological capacity building, and support for institutions. The lack of international
collaboration – both north-south and south-south – has been improved through the
formation of the GLOWA Volta Research network. The strong local presence was a
keystone for the successful dissemination of the research results and information.
The legacy of the project refers to the sustainability of its results. Besides the tools,
especially the Geoportal, and research infrastructure which are continued and used in
the Basin, the greatest, sustaining, legacy is related to the capacity building efforts that
went along with the research. With the local trainings and education of graduate
students, local expertise was created or improved in many disciplines or research areas,
and practice. The involvement of a large number of students and institutions from the
basin created a sense of ownership which contributed much to the acceptance of the
models and outputs. Especially the large fraction of African students that has returned to
the Volta Basin is to be mentioned in this regard, as they bring both the required
expertise and the motivation to implement research results. Those who have found
employment in the local universities and research facilities furthermore act as multipliers
in that they pass on the knowledge they have acquired during their studies in the
GLOWA Volta Project. The networks that were established in the course of the project,
but also the network that formed among the students that participated in the project,
continues to thrive and will support future, interdisciplinary problem solving. Finally, the
Volta Basin Authority may be mentioned once again, which we have supported in its
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establishment, with the firm conviction that it will develop into a strong institution
dedicated to the management of natural resources in the Volta Basin.
Although the operational research in the GVP has come to an end in May 2009, the
involvement in the Basin and the interaction with the GLOWA Volta counterparts,
especially the VBA, will persist. The Center for Development Research was recently
granted an 18 month project on “Sustainable Development of Research Capacity based
on the GLOWA Volta Project in West Africa”, which builds on three pillars:
- strengthening research capacity & networks in the Volta Basin based on GVP
tools and models
- strengthening the Volta Basin Authority
- support implementation and use of GVP outputs
These objectives are addressed in a series of selected training efforts, with the goal to
strengthen the VBA and its research network by further developing its research capacity.
Finally, we would like to express our sincere gratitude to all of the students, staff,
scientists, and partners who participated in this project and helped making it a success.
Our special thanks go to the countries of Burkina Faso and Ghana who have been very
welcoming and supportive hosts. They have welcomed us as guests and researchers,
provided much appreciated support, and took great interest in the project‟s research and
scientific results.
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4. Publications
4.1 Completed Theses
Amisigo, B. (2006). Modeling Riverflow in the Volta basin of West Africa. A data-driven framework. Doctoral Thesis. Antwi, B. (2006). Using Caesium-137, Lead-210 and particle size fractions to model spatial soil eroison in the forest-savannah transition ecology of the Volta Basin of Ghana. Doctoral Thesis. Bagayoko, F. (2006). Impact of land-use intensity on evaporation and surface runoff. Process and parameters for eastern Burkina Faso, West Africa. Doctoral Thesis. Berg, J. v. d. (2008). Contribution of informal shallow groundwater irrigation to livelihood security in the White Volta Basin: current status and future sustainability. A case study in the Upper East Region, Ghana. Master Thesis., Delft University of Technology, The Netherlands Boko, G. H. (2009). A classification of the different land use systems in the Volta basin with respect to the water cycling by means of Reference Evapotranspiration according to FAO standards. Master Thesis Ouagadougou University. Dabiré, I. W. P. (2007). Gestion durable des petits bassins versants du bassin de la volta : simulation bioéconomique des options de gestion alternative dans le sud-ouest du Burkina Faso. Master Thesis, Ouagadougou University. Eguavoen, I. (2007). Now you have a new pump, you have to manage it. Household water management, water rights and institutional change in Northern Ghana. Doctoral Thesis. Institute of Social Anthropology, Philosophical Faculty, Cologne/ Germany. Faulkner, J. (2006). Water use, productivity, and profitability in small-scale irrigation schemes in Ghana's Upper East Region. Doctoral Thesis, Cornell University. Förster, J. (2009 (expected in June)). The Potential of Reducing Emissions from Deforestation and Degradation (REDD) in Western Ghana. Master Thesis. Friesen, J. C. (2008). Regional vegetation water effects on satellite soil moisture estimations for West Africa. Doctoral Thesis, Delft University of Technology, The Netherlands. Hauck, J. (2010). Managing Social-Ecological Systems for Resilience: Fisheries in the Small Reservoirs of Northern Ghana. Doctoral Thesis. Hoog, J. v. d. (2007). Stem compression measurements in central and northern Ghana, Delft University of Technology, The Netherlands.
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Jung, G. (2006). Regional climate change and the impact on hydrology in the Volta basin of West Africa. Doctoral Thesis. Kasei, R. (2006). Determination of Sensible Heat Flux from Large Aperture Scintillometer Measurements in the Volta Basin of Ghana., University of Cape Coast/ Ghana, Wageningen University/ Netherlands. Kasei, R. (2009). Modelling impacts of climate change on water resources in the Volta Basin West Africa. Doctoral Thesis. Kpongor, D. S. (2007). Spatially Explicit Modeling of Sorghum Production in a Complex Terrain in a Semi-Arid Region of Ghana using APSIM. Doctoral Thesis. Rheinische Friedrich Wilhelms Universität, Bonn/ Germany. Laubach, J. (2008). Aufbau eines Geoportals als komponentenbasiertes Informationssystem für ein Projekt der Entwicklungsforschung (GLOWA Volta). Diploma Thesis. Laux, P. (2009). Statistical modeling of precipitation for agricultural planning in the Volta Basin of West Africa. Doctoral Thesis. Lazare, T. (2007). Modeling of vegetation dynamics and its contribution to the water balance in semi-arid lands of West-Africa, University of Bonn. Machwitz, M. (2009 (expected end of the year)). Land cover mapping in the GLOWA Volta basin using MODIS time-series observations and multi-agent models. Mandé, T. (2007). Conception d'un modèle d'optimisation stochastique pour l'agriculture dans un bassin versant du Burkina Faso. Master Thesis. Ouagadougou University, Ouagadougou/ Burkina Faso. Mandé, T. (2007). Variabilité climatique et risque alimentaire: un modèle d'optimisation stochastique d'une exploitation agricole burkinabé. Master Thesis. Institute 2iE,
Ouagadougou/ Burkina Faso. Mdemu, M. V. (2008). Water productivity in medium and small reservoirs in the Upper East Region (UER) of Ghana. Doctoral Thesis. Neumann, R. (2005). Stochastische hydrologische Simulationen. Diploma Thesis, Hochschule für Technik, Wirtschaft und Sozialwesen Regensburg & Forschungszentrum Karlsruhe/ Germany. Nyarko, B. K. (2007). Floodplain Wetland-River flow Synergy in the White Volta Basin of Ghana. Geographic Institute. Rheinische Friedrich Wilhelms University, Bonn/ Germany. Obuobie, E. (2008). Estimation of Groundwater Recharge in the Context of Future Climate Change in the White Volta River Basin, West Africa. Faculty of Mathematics and Natural Sciences. Bonn, University of Bonn/ Germany.
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Sandwidi, J.-P. W. (2007). Groundwater potential to supply population demand within the Kopienga dam basin in Burkina Faso. Doctoral thesis. Bonn/ Germany. Schindler, J. (2009). A multi-agent system for simulating land-use and land-cover change in the Atankwidi catchment of Upper East Ghana. Doctoral Thesis. Schlömann, A. (2006). Bilanzierung des Bewässerungsfeldbaus im Upper East (Ghana) mittels Fernerkundung und dynamischer Modellierung. Diploma Thesis. Geographical Institute. Rheinische Friedrich-Wilhelms-Universität, Bonn/ Germany. Schuettemeyer, D. (2005). The surface energy balance over drying semi-arid terrain in West Africa. Wageningen University/ Netherlands. Smits, J. (2008). Spatial and temporal accuracy of techniques used for moisture states and flux estimation for large-scale areas. A Western Africa Case Study. Master Thesis, Delft University of Technology, The Netherlands. Tia, L. (2007). Modeling of vegetation dynamics and its contribution to the water balance in semi-arid lands of West Africa. Doctoral Thesis. Tsuma, W. (2009). Actors, Alliances and Power in Negotiations Unequal Distribution of Mining Benefits in Tarkwa‟s Gold Mining Area of Western Ghana. Doctoral Thesis. van der Schaaf, C. (2007). Flowing Structures and Concrete Struggles: irrigation management and institutional change in centre-eastern Burkina Faso. Doctoral Thesis. Wagner, S. (2008). Water Balance in a Poorly Gauged Basin in West Africa Using Atmospheric Modelling and Remote Sensing Information. Doctoral Thesis. Institut für Wasserbau, Universität Stuttgart, Stuttgart/ Germany.
4.2 Journal Articles
Abukari M., Schiffer E. & Hauck J. (2009) Influence Network Mapping: Mapping Power Asymmetry of Water User Groups in IFAD-supported Projects in Northern Ghana. IFAD – InnoWat Tool Sheet. Afari-Sefa V., Rodgers C., Plotnikova M. & Vlek P. (2007) Implications of Increasing Water Demand and Potential Climate Change in the Volta Basin for Ghana's Socio-economic Development. International Journal of Water Resources Development or Journal of International Agriculture (proposed for submission). Ahrends H., Mast M., Rodgers C. & Kunstmann H. (2008) Coupled Hydrological-Economic Modelling for Optimised Irrigated Cultivation in a Semi-arid Catchment of West Africa. Environmental Modelling and Software 23, 385-95.
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Ajayi A. E., van de Giesen N. & Vlek P. L. G. (2007) A numerical model for simulating Hortonian overland flow on tropical hillslopes with vegetation elements. Hydrological Processes 22, 1107-18. Amisigo B. A. & Giesen N. v. d. (2007) Monthly Streamflow Prediction in the Volta Basin of West Africa: A SISO NARMAX Polynomial Modeling. Physics and Chemistry of the Earth 33. Amisigo B. A. & van de Giesen N. (2005) Using a spatio-temporal dynamic state-space model with the EM algorithm to patch gaps in daily riverflow series, with examples from the Volta Basin, West Africa. Hydrology and Earth System Sciences Discussions. Amisigo B. A., van de Giesen N. & Andah W. E. I. (2007) A Hybrid Metric-Conceptual (HMC) Model for Monthly Riverflow Prediction in the semi-arid Volta Basin of West Africa. Journal of River Basin Management 5, 57-68. Ampomah B. Y., Adjei B. A. & Youkhana E. (2008) The Transboundary Water Resources Management Regime of the Volta Basin. ZEF Working Paper Series 28. Annor F. O., van de Giesen N., Liebe J., van de Zaag A., Tilmant A. & Odai S. N. (2009) Delineation of small reservoirs using radar imagery in a semi-arid environment: A case study in the upper east region of Ghana. Physics and Chemistry of the Earth 34, 309-15. Bagayoko F., Yonkeu S. & Giesen N. C. v. d. (2006a) The effect of seasonal dynamics of vegetation cover on Land Surface Models: a case study of NOAH LSM over a savanna farm land in Eastern Burkina Faso, West Africa. Hydrology and Earth System Sciences Discussions Bagayoko F., Yonkeu S. & van de Giesen N. (2006b) Energy balance closure and footprint analysis using Eddy Covariance measurements in Eastern Burkina Faso, West Africa. Hydrology and Earth System Sciences Discussions 3. Barbier B., Dembelé Y. & Compaoré L. (2006) Les usages alternatifs de l'eau au Burkina Faso : Les options. Sud Sciences et technologies - semestriel des Ecoles Inter-Etats EIER-ETSHER. Barbier B., Maiga A. & Konaté Y. (2008) Quels défis pour la gestion de l'eau en Afrique de l'Ouest? Cahiers de l'Agricuture. Barbier B. & Maïga H. H. (2006) Les ressources en eau en Afrique de l'Ouest: Atouts et menaces. Carrefour Africain, 5p. Bhaduri A. & Barbier E. (2008) Political Alturism of Water Sharing. B.E. Journals in Economic Analysis & Policy. 8. Bhaduri A., Barbier E. & Manna U. (2009) Exploring economic incentives to the farmers for soil carbon sequestration (Work in progress).
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Bhaduri A. & Barbier E. B. (2008) International water transfer and sharing: the case of the Ganges River. Environment and Development Economics 13, 29-51. Bhaduri A., Liebe J. & Perez N. (2009) M3 Water-Policy Model for Efficient Transboundary Allocation of water (Work in progress). Bhaduri A., Manna U. & Barbier E. (2009) Stochastic Differential Games: Numerical Methods and Applications to Transboundary Water Sharing (Work in progress). Bhaduri A., Perez N. & Liebe J. (2008) Scope and Sustainability of Cooperation in Transboundary Water Sharing of the Volta River. ZEF – Discussion Papers On Development Policy 124. Bhaduri A., Perez N. & Liebe J. (2009) Bi-lateral Negotiations for a Sustainable Agreement in the Transboundary Allocation of Water in the Volta River Basin of West Africa. (Submitted). Bharati L., Rodgers C., Erdenberger T., Plotnikova M., Shumilov S., Vlek P. & Martin N. (2008) Integration of Economic and Hydrologic Models: Exploring Conjuctive Irrigation Water Use Strategies in the Volta Basin. Agricultural Water Management 95, 925-36. Braimoh A. K. (2006) Random and systematic Land Cover Transitions in Northern Ghana. Agriculture, Ecosystems & Environment 113, 254-63. Braimoh A. K. & Craswell E. T. (2006) Assessing Global Water Systems Research. Eos Transactions American Geophysical Union 87, 159. Braimoh A. K. & Vlek P. L. G. (2006) Soil Quality and Other Factors Influencing Maize Yield in Northern Ghana. Soil Use and Management 22, 165-71. Brümmer C., Brüggemann N., Butterbach-Bahl K., Falk U., Szarzynski J., Vielhauer K., Wassmann R. & Papen H. (2008) Soil-atmosphere exchange of N2O and NO in near-natural savanna and agricultural land in Burkina Faso (W. Africa). Ecosystems 11. Brümmer C., Brüggemann N., Wassmann R., Falk U., Szarzynski J. & Papen H. (2007) Biosphere-atmosphere exchange of N2O, CH4 and CO2 in natural savannah and rainfed agriculture in Burkina Faso (W Africa). Geophysical Research Abstracts 9. Brümmer C., Falk U., Papen H., Szarzynski J., Wassmann R. & Brüggemann N. (2008b) Diurnal, seasonal and inter-annual variation in carbon dioxide and energy exchange in shrub savanna in Burkina Faso (W. Africa) Journal of Geophysical Research 113. Brümmer C., Papen H., Wassmann R. & Brüggemann N. (2009) Fluxes of CH4 and CO2 from soil and termite mounds in South-Sudanian savanna of Burkina Faso (W. Africa). . Global Biogeochemical Cycles 23. Brümmer C., Papen H., Wassmann R. & Brüggemann N. (2009) Termite mounds as hot spots of nitrous oxide emissions in South-Sudanian savanna of Burkina Faso (W. Africa). Geophysical Research Letters 36.
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Brunner A. C., Dikau R. & Vlek P. L. G. (2009) Between emergence and reductionism – Modelling soil erosion at different scales in South-West Burkina Faso. Geomorphology (work in progress). Brunner A. C., Park S. J., Ruecker G. R. & Vlek P. L. G. (2008) Erosion modelling approach to simulate the effect of land management options by considering catenary soil development and farmers perception of soil loss on a hillslope in Uganda. Land Degradation & Development (In revision) 19, 623-35. Brunner A. C. & Vlek P. L. G. (2009) Quantification of sediment budgets of small reservoirs in southwestern Burkina Faso by bathymety, sediment coring and 137Cs measurements. Geoderma (work in progress). Codjoe S. (2006) Migrant versus indigenous farmers: An analysis of factor affecting agricultural land use in the transitional agro-ecological zone of Ghana, 1984-2000. Danish Journal of Geography 106, 103-13. Codjoe S. N. (2006) Population Dynamics and Natural Resources in the Volta River Basin of Ghana. Ghana Journal of Development Studies 3, 66-82. Colditz R., Conrad C., Wehrmann T., Schmidt M. & Dech S. (2008) TiSeG – A flexible software tool for time series generation of MODIS data utilizing the quality assessment science data set. IEEE Transactions on Geoscience and Remote Sensing . Compaore H., Hendrickx J. M., Hong S., Friesen J., van de Giesen N. C., Rodgers C., Szarzinsky J. & Vlek P. L. G. (2008) Evaporation mapping at two scales using optical imagery in the White Volta Basin. Physics and Chemistry of the Earth 33, 127-44. de Jeu R., Wagner W., Holmes T., Dolman H., van de Giesen N. & J. F. (2008) Global Soil Moisture Patterns Observed by Space Borne Microwave Radiometers and Scatterometers. Surveys in Geophysics (submitted) 29, 399-420 doi:10.1007/s10712-008-9044-0. De Lange R., Beck R., van de Giesen N., Friesen J., de Wit A. & W. W. (2008) Scatterometer derived soil moisture calibrated for soil texture with a one-dimensional water flow model. IEEE Transactions on Geoscience and Remote Sensing 46, 4041-9. Eguavoen I. (2008) Changing household water rights in rural Northern Ghana. Development 51, 126-9. Eguavoen I. (2008) How Water Users Operationalize Policy. The Case of Pump Communities in the Kassena-Nankana District of Ghana. Ghana Journal of Development Studies 5, 58-79. Eguavoen I. & Youkhana E. (2008) Small towns face big challenge. Water system management after the water sector reform in Ghana. ZEF Working Paper Series 26.
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Engel S., Iskandarani M. & Useche M. d. P. (2006) Household Water Security in the Ghanaian Volta Basin: Why do people still not use improved water sources? International Journal of River Basin Management 5, 1-6. Engel S., Iskandarani M. & Useche M. d. P. (2007) Demand and supply of improved water in the Ghanaian Volta Basin. Journal of River Basin Management 5. Falk U. (forthcoming) Beyond the visible. Application of infra-red thermography within micrometeorological forest canopy research. BioScience. Falk U., Brüggemann N., Szarzynski J., Brümmer C. & Vlek P. L. G. (forthcoming-a) Radiation balance and energy fluxes of a West African savanna ecosystem (Bontioli National Park, Burkina Faso). Int. Journal of Biometeorology. Falk U., Brümmer C., Brüggemann N., Wassmann R. & Szarzynski J. (2007) Fluxes of carbon, water, and energy above a natural savannah in Burkina Faso, West-Africa. Geophysical Research Abstracts 9. Falk U., Brümmer C., Brüggemann N., Wassmann R., Szarzynski J. & Papen H. (2008) Diurnal, seasonal and inter-annual variation in carbon dioxide and energy exchange in shrub savanna in Burkina Faso (W. Africa). Journal of Geophysical Research 113. Falk U., Hendrickx J. M. H., Conrad C. & Vlek P. L. G. (forthcoming-b) Scintillometry, Eddy Covariance and Remote Sensing for Evapotranspiration Mapping in West-Africa. Int. Journal of Remote Sensing. Falk U., Szarzynski J., Landmann T. & Schmidt M. (2007) Impact of climate and environmental changes on regional biodiversity. Results and perspectives from the BIOTA West Africa and GLOWA Volta research networks in West Africa. Geophysical Research Abstracts 9. Falk U., Tia L. & Vlek P. L. G. (forthcoming) The impact of microclimatic conditions on transpiration and water uptake of different West African savanna tree species. Journal of Biometeorology. Faulkner J., Steenhuis T., Giesen N. v. d., Andreini M. & Liebe J. (2008) Water use and productivity of two small reservoir irrigation schemes in Ghana‟s Upper East Region. Irrigation and Drainage Systems 57, 151-63. Fosu M., Kühne R. F. & Vlek P. L. G. (2007) Mineralization and Microbial Biomass Dynamics during Decomposition of four Leguminous Residues. Journal of Biological Sciences 7, 632-7. Friesen J., Rodgers C., Oguntunde P. G., Hendrickx J. M. H. & van de Giesen N. (2007) Hydrotope-based protocol for average soil moisture determination of large areas With results from an observation campaign in the Volta Basin, West Africa. IAHS Publication 316.
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Friesen J., Rodgers C., Oguntunde P. G., Hendrickx J. M. H. & van de Giesen N. (2008) Hydrotope-Based Protocol to Determine Average Soil Moisture Over Large Areas for Satellite Calibration and Validation With Results From an Observation Campaign in the Volta Basin, West Africa. IEEE Transactions on Geoscience and Remote Sensing 46, 1995-2004. Friesen J., van Beek C., Selker J., Savanije H. H. G. & van de Giesen N. (2008) Tree Rainfall Interception Measured by Stem Compression. Water Resources Research 44. Friesen J., Winsemius H. C., Beck R., Scipal K., Wagner W. & van de Giesen N. (2007) Spatial and seasonal patterns of diurnal differences in ERS Scatterometer soil moisture data in the Volta Basin, West Africa. IAHS-AISH Publication 316, 47-55. Fuest V. & Haffner S. A. (2007) PPP-policies, practices and problems in Ghana´s urban water supply. Water Policy 9, 169-92. Gleisberg K. (forthcoming) Simulating land-use changes and related community dynamics in Ioba province, Burkina Faso. Ecology and Development Series. Gleisberg K., Le Q. B. & Vlek P. L. G. (forthcoming) Integrated impact assessment of policy intervention alternatives on land-use/cover and community dynamics using a multi-agent simulation model. Ecological Modeling/ Land Use Policy/ Land Use Science/ World Development. Grote R., Lehmann E., Brümmer C., Brüggemann N., Szarzynski J. & Kunstmann H. (2009) Modelling and observation of biosphere–atmosphere interactions in natural savannah in Burkina Faso, West Africa. Physics and Chemistry of the Earth 34, 251-60. Hafeez M., Andreini M., Liebe J., Friesen J., Marx A. & an de Giesen N. (2007) Hydrological parameterization through remote sensing in Volta Basin, West Africa. International Journal of River Basin Management 5. Hafeez M. M., Bouman B. A. M., van de Giesen N., Mushtaq S. & Vlek P. L. G. (2008) Water Re-Use and Cost-Benefit of Pumping at Different Spatial Levels in a Rice Irrigation System in UPRIIS, Philippines. Physics and Chemistry of the Earth 33. Hauck J. & Schiffer E. (2009) Net-Map Case Study: Research on Fisheries Management in Small Multipurpose Reservoirs. Challenge Program No. 46: Small Multi-Purpose Reservoir Ensemble Planning – Tool Kit. Hauck J. & Youkhana E. (2008) Claim and reality of Community based water management. . Water Alternatives Hauck J. & Youkhana E. (2008) Histories of water and fisheries management in Northern Ghana. ZEF Working Paper Series 32.
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Hendrickx J. M. H., J. Kleissl, J.D. Gómez-Vélez, S. Hong, J.R. Fábrega-Duque, D. Vega, H.A. Moreno-Ramírez & Ogden F. L. (2007) Scintillometer networks for calibration and validation of energy balance and soil moisture remote sensing algorithms. Proc. International Society for Optical Engineering. Hennenberg K. J., Goetze D., Szarzynski J., Orthmann B., Reiniking B., Steineke I. & Porembski S. (2008) Detection of seasonal variability in microclimatic borders and ecotones between forest and savanna Basic and Applied Ecology 9, 275-85. Jung G. & H. K. (2007) High-resolution Regional Climate Modelling for the Volta Basin of West Africa. Journal of Geophysical Research 112. Jung G., Wagner S. & Kunstmann H. (2009) Joint Climate-Hydrology Modelling: An Impact study for the Data Sparse Environment of the Volta Basin in West Africa. Water Resources Research (Submitted). Jung H. Y., T.S. Hogue, L. K. Rademacher & Meixner T. (2009) Impact of Wildfire on Source Water Contributions in Devil Creek, CA: Evidence from End-Member Mixing Analysis. Hydrological Processes 23. Kanazué B., Barbier B. & Thiombiano T. (2008) Production d'électricité et réduction des gaz à effet de serre au Burkina Faso. Cahiers du Cedres . Kasei R. (forthcoming) Changes in Hydrological time series – A challenge for water management in the Volta Basin (in revision). Kasei R. (forthcoming) Modelling Net Primary Productivity at regional scale in West Africa using 250 m MODIS data and different climate data – a comparison (submitted). Kasei R., Diekkrüger B., Vlek P. L. G., Leemhuis C. & Rodgers C. (2008) Drought Frequency in the Volta Basin of West Africa. . Journal Land Use and Environmental Sustainability (in press). Kpongor D. S. (2007) Modeling the impacts of contrasting nutrient and residue management practices on grain yield of Sorghum (Sorghum bicolor (L) Moench) in a semi-arid region of Ghana using APSIM. Field Crops Research. Kunstmann H., Jung G., Wagner S. & Clottey H. (2008) Integration of atmospheric sciences and hydrology for the development of decision support systems in sustainable water management. Physics and Chemistry of the Earth, Parts A/B/C 33, 165-74. Landmann T., Machwitz M., Bao Q. L., Tamene L. & L.P.G. V. (forthcoming) A land cover change synthesis study for the GLOWA Volta Basin in West Africa using time trajectory satellite observations and cellular automation models . Laube W. (2007) Promise and Perils of Water Reform. Perspectives from Northern Ghana. Afrika Spectrum 3, 419-37.
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Laube W. (2007) The promise and perils of water reforms: Perspectives from Northern Ghana. Afrika Spectrum 42, 419-37. Laube W., Ampadu F. & Spalthoff. D. (2007) Assessment of Ghanaian Civil Society Organisations in the Water Sector. ZEF Laube W., Awo M. & Schraven B. (2008) Erratic Rains and Erratic Markets: Environmental change, economic globalisation and the expansion of shallow groundwater irrigation in West Africa. ZEF Working Paper 30. Laube W., Awo M. & Schraven B. (2009) Smallholder adaptation to climate change: dynamics and limits in Northern Ghana. Climatic Change (submitted). Laube W., Leemhuis C. & Amisigo B. (2008) Impact of Climate Change on the Black Volta Basin and the Bui Dam GLOWA Volta Policy Brief. Laube W. & Schraven B. (2007) Riverine small-scale irrigation as local adaptation process in Northern Ghana towards climate and environmental change: impact, risks and opportunities. (In progress). Laube W. & Youkhana E. (2006) Cultural, Socio-Economic and Political Constraints for Virtual Water Trade: Perspectives from the Volta Basin, West Africa. ZEF Working Paper 13. Laube W. & Youkhana E. (2008) Virtual water trade: political and social challenges in the Volta basin. Water Politics. Lautze J., Barry B. & Youkhana E. (2006) Changing Interfaces in Volta basin management: Customary, National and Transboundary. ZEF Working Paper Series 13, Center for Development Research, Bonn. Lautze J., Barry B. & Youkhana E. (2008) Changing paradigms in the Volta Basin Water Management: Customary, National and Trans-boundary Water Policy 10, 577–94. Laux P. (2009) Statistical Modeling of Precipitation for Agricultural Planning in the Volta Basin of West Africa. Disseration Mitteilungen / Institut für Wasserbau der Universität Stuttgart 179. Laux P., Jäckel, G., Tingem, M., Kunstmann, H. (2009) Onset of the rainy season in West Africa. Geophysical Research Abstracts 11. Laux P., Jöckel, G., Tingem, M., Kunstmann, H. . (2009) Impact of climate change on agricultural productivity under rainfed conditions in Cameroon – A benchmark method to improve attainable crop yield (work in progress). Laux P. & Kunstmann H., 044005. (2008) Detection of regional weekly weather cycles across Europe. Environmental Research Letters 3, http://www.iop.org/EJ/toc/1748-9326/3/4.
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Laux P., Kunstmann H. & A. B. (2008) Predicting the Regional Onset of the Rainy Season in West Africa. International Journal of Climatology 28, 329-42. Laux P., S. W., A. W., J. J., A. B. & H. K. (2009) Modelling daily precipitation features in the Volta Basin of West Africa. International Journal of Climatology DOI: 10.1002/joc.1852; http://www3.interscience.wiley.com/journal/4735/home?CRETRY=1&SRETRY=0 Laux P., Wagner A., Jacobeit J., Bardossy B. & Kunstmann H. (2009) Modelling daily precipitation features in the Volta Basin in West Africa. International Journal of Climatology 29, 937-54. Laux P., Wagner S., Wagner A., Kunstmann H. & Bárdossy A. (2009) Modelling daily precipitation features for agricultural planning in the Volta basin. International Journal of Climatology 29, 937-54. Laux P., Wagner, S., Wagner, A., Jacobeit, J., Bárdossy, A., Kunstmann, H. (2009) Modelling Daily Precipitation Features in the Volta Basin of West Africa. International Journal of Climatology 29, 937-54. Le B. Q., Park S., Vlek L. G. & Cremers A. B. (2008) Land Use Dymanic Simulator (LUDAS). A multi-agent system model for simulating spacio-temporal of coupled human-landscape system I. Structure and theoretical specification. Ecological Informatics 3. Le Q. B., Park S. J., Vlek P. L. G. & Cremers A. B. (2008) Land-Use Dynamic Simulator (LUDAS): A multi-agent system model for simulating spatio-temporal dynamics of coupled human–landscape system. I. Structure and theoretical specification. Ecological Informatics 3, 135-53. Le Q. B., Tamene L. & Vlek P. L. G. (2008) Multi-scale assessments of land degradation in West Africa. ZEF Annual Report 2007/2008, Center for Development Research (ZEF), University of Bonn, 9-12. Leemhuis C., Jung G., Kasei R. & Liebe J. (2009) The Volta Basin Water Allocation System: Assessing the impact of the agricultural development on the water resources of the Volta basin, West Africa. . Advances in Geoscience 21, 57–62. Leemhuis C., Jung G., R. K. & Liebe J. (2009) Reservoir impact assessment in sub-Saharan Africa: The Volta Basin Water Allocation System (VB-WAS). Geophysical Research Abstracts 11, EGU2009-9342. Leemhuis C., Rodgers C., Agyare W. & Jung G. (2007) Integrated assessment in a data-scarce environment: the use of model ensembles to enable rational water management in the Volta Basin, West Africa. Geophysical Research Abstracts 9[5-2]. Leemhuis C., Rodgers C., Plotnikova M. & Jung G. (forthcoming) Analysis of the hydrological implications of Bui Gorge Dam construction in eastern Ghana. (In progress).
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Liebe J., N. van de Giesen , M. Andreini, M. T. Walter & Steenhuis T. S. (2009) Determining watershed response in data poor environments with remotely sensed small reservoirs as runoff gauges. Water Resources Research 45. Liebe J., N. van de Giesen, M.S. Andreini, T.S. Steenhuis & Walter M. T. (2009) Suitability and Limitations of ENVISAT ASAR for Monitoring Small Reservoirs in a Semiarid Area. IEEE Transactions on Geoscience and Remote Sensing 47, 1536-47. Machwitz M., Schramm M., Landmann T. & Dech S. (2008) Remote Sensing based determination of percentage tree cover in West Africa. Geophysical Research Abstracts 10. Marx A., Kunstmann H., Schüttemeyer D. & Moene A. F. (2008) Uncertainty analysis for satellite derived sensible heat fluxes and scintillometer measurements over Savannah environment and comparison to mesoscale meteorological simulation results. Agricultural and Forest Meteorology 148, 656-67. Marx A., Schuettemeyer D., Kunstmann H. & Moene A. (2008) Uncertainty analysis for satellite derived sensible heat fluxes and scintillometer measurements over Savannah environment and comparision to mesoscale meteorological simulation results. Agricultural and Forest Meteorology 148, 656-67. Mdemu M. V., Rodgers C., Vlek P. L. G. & Borgadi J. J. (2009) Water productivity (WP) in reservoir irrigated schemes in the upper east region (UER) of Ghana Physics and Chemistry of the Earth 34, 324-8. Neumann R., Jung G., Laux P. & Kunstmann H. (2007) Climate trends of temperature, precipitation and river discharge in the Volta Basin of West Africa. International Journal of River Management 5, 17-30. Nyarko B. K., Diekrüger B., Van de Giesen N. & P. V. (2009) Floodplain Wetland Mapping for Environmental flow assessment in the White Volta Basin. International Journal of Remote Sensing (submitted). Nyarko B. K., Essumang D. K., Eghan J. M., Reichert B., Van de Giesen N. & Vlek P. (2009) Use of isotopes to study floodplain-wetland and River flow interaction in the White Volta Basin, Ghana. Isotopes in Environmental and Health Studies (submitted). Obuobie E. (2009) Climate Change Impacts on Hydrology and Water Resources in the White Volta River Basin, West Africa (work in progress). Obuobie E. (2009) Estimation of Groundwater Recharge in the White Volta River Basin using Chloride Mass Balance and Water Table Fluctuation Techniques (work in progress). Obuobie E., Diekkrueger B. & Liebe J. (2009) Impact of Future Climate Change on Streamflow in the White Volta River Basin, West Africa. Geophysical Research Abstracts 11, EGU2009-569.
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Oguntunde P. G., Abiodun B. J., Ajayi A. E. & van de Giesen N. (2008) Potential impact of charcoal production on hydro-physical properties of soil, rainfall infiltration and runoff. Journal of Plant Nutrition and Soil Science 171, 591-6. Oguntunde P. G., J. Friesen, Nick van de Giesen & Savenije H. H. G. (2006) Hydroclimatology of the Volta River Basin in West Africa: Trends and variability from 1901 to 2002 Physics and Chemistry of the Earth 31, 1180-8. Oltchev A., Ibrom A., Ross T., Falk U., Rakkibua G., Radler K., Grote S., Kreilein H. & Gravenhorst G. (2007) A modelling approach for simulation of water and carbon dioxide exchange between multi-species tropical rain forest and the atmosphere Ecological Modelling 10. Rodgers C., Agyare W. & Leemhuis C. (2007) Integrated assessment in data-scarce environment: the use of model ensembles to enable rational water management in the Volta Basin, West Africa. Geophysical Research Abstracts 9. Rodgers C., Laube W. & Falk U. (2007) Alternative Irrigation Development Paths in an Uncertain Climate: Farmer-Initiated Irrigation Development in Northern Ghana. Climate and Water. Proceedings of Third International Conference on Climate and Water. Finnish Environment Institute, 398-403. Rodgers C., Laube W., van de Giesen N., Vlek P. L. G. & Youkhana E. (2006) The GLOWA Volta Project: A Framework for Water Resource Decision-Making and Scientific Capacity Building in a Transnational West African Basin. Water Resources Management 21, 295-313. Sandker M., Nyame S. K., Förster J., Collier N., Yeboah D., Blas D. E.-d., Machwitz M., Shepherd G., Vaatainen S., Garedew E., Etoga G., Ehringhaus C., Anati J., Quarm O. D. K. & Campbell B. (2009) REDD payments as incentive for reducing forest loss: A case from Ghana. Conservation letters (submitted). Schiffer E. & Hauck J. (2010) Net-Map: Collecting Social Network data and Facilitating Network Learning through Participatory Influence Network Mapping. Field Methods. Schindler J. (forthcoming) A multi-agent system for simulating land-use and land-cover changes in the Atankwidi catchment in Upper Eastern Ghana. Ecology and Development Series (in press). Schramm M., Landmann T., Lohmann P. & Heipke C. (2008) Ein neues Modell für eine spektrale Entmischung ohne genaue Endmemberspektren. Photogrammetrie, Fernerkundung, Geoinformation 5, 351-62. Schüttemeyer D., Moene A. F., Holtslag A. A. M. & Bruin H. A. R. d. (2006) Evaluation of different parameterizations for land surface schemes over drying terrain in West Africa. Geophysical Research Abstracts 8.
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Schuettemeyer D., Moene A. F., Holtslag A. A. M. & de Bruin H. A. R. (2008) Evaluation of two land-surface schemes used in terrains of increasing aridity in West Africa. Journal of Hydrometeorology 9, 173-93. Schuettemeyer D., Moene A. F., Holtslag A. A. M., de Bruin H. A. R. & van de Giesen N. (2006) Surface fluxes and characteristics of drying semi-arid terrain in West Africa. Boundary-Layer Meteorology. Schuttemeyer D., Schillings C., Moene A. F. & Bruin H. A. R. d. (2007) Satellite-Based actual evapotranspiration over drying semiarid terrain in West-Africa. Journal of Applied Meteorology and Climatology 46, 97–111. Segai D. & Le Q. B. (forthcoming) Inter-district migration flows in Ghana: analysis of socio-economic and environmental factors. Applied Spatial Analysis and Policy (in progress). Sharma A. & Bhaduri A. (forthcoming) The “tipping point” in Indian agriculture: Understanding the Withdrawal of Indian Rural Youth Asian Journal of Agriculture and Development. . Tamene L., Alamirew D., Agyare W., Rodgers C. & Vlek P. L. G. (forthcoming) Expert-based and quantitative analysis of reservoir sedimentation and controlling factors in the White Volta basin. Geomorphology. Tamene L., Le Q. B., Liebe J. & Vlek P. L. G. (2009) Developing a decision support tool for landscape planning and management to minimize land and water degradation. Geophysical Research Abstracts 11. Tamene L. D., Le Q. B. & Vlek P. L. G. (forthcoming) Assessing the spatio-temporal dynamics of land degradation in Sub-Saharan Africa using time-series AVHRR NDVI data and CRU dataset. Taylor J. C., van de Giesen N. & Steenhuis T. S. (2006) West Africa: Volta discharge data quality assessment and use. Journal of the American Water Resources Association 42, 113-1126. Tia L., Szarzynski J. & Vlek P. L. G. (2007) Ecological modeling of tree patterns and diversity as a means of classifying savanna landscapes: Remote sensing and GIS-based mapping. Geophysical Research Abstracts 9. Tsegai D. (2007) Migration as a household decision: What are the Roles of Income Differences? Insights from the Volta Basin of Ghana. The European Journal of Development Research 19, 305-26. Tsegai D. (forthcoming) Migration in the Volta Basin of Ghana: The role of Remittances. African Development Review (in revision).
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van de Giesen N., Rodgers C. & Vlek P. (2007) The GLOWA Volta Project: Interdisciplinary analysis of the impact of global change on a river basin in West Africa. JRBM 5. Vlek P. L. G., Le Q. B. & Tamene L. (2008) Land decline in Land-Rich Africa: a creeping disaster in the making. CGIAR Science Council Secretariat, Rome, Italy, 62. Wagner S., Kunstmann H. & Bárdossy A. (2006) Model based distributed water balance monitoring of the White Volta catchment in West Africa through coupled meteorological- hydrological simulations. Advances of Geosciences 9, 39-44. Wagner S., Kunstmann H., Bárdossy A., Conrad C. & Colditz R. (2009) Water balance estimation of a poorly gauged catchment in West Africa using dynamically downscaled meteorological fields and remote sensing information. Physics and Chemistry of the Earth 34, 225-35. Wagner S., Kunstmann H., Bárdossy A. & C. C. (2007) Water balance simulations in a poorly gauged basin using different meteorological and land surface data sources. Geophysical Research Abstracts 9. Wittig R., König K., Schmidt M. & Szarzynski J. (2007) A Study of Climate change and Anthropogenic Impacts in West Africa Environmental Science and Pollution Research – International. Wolf S., Fuest V. & Asante F. (2007) Water and electricity sector reforms in Ghana: Back on track? JRBM 5. Yilma T., E. Berg & Berger T. (2007) The Agricultural Technology-Market Linkage under Liberalisation in Ghana: Evidence from Micro Data. Journal of African Economies 17, 62-84. Youkhana E. (2009) Gates and gaps in transboundary flood management. Communication structures, networks and information flows (Work in progress). Youkhana E. & Laube W. (2006) Cultural, Socio-Economic and Political Constraints for Virtual Water Trade. Perpectives from the Volta Basin, West Africa. ZEF Working Paper Series 13.
4.3 Books
Eguavoen, I. (2008). The Political Ecology of Household Water in Northern Ghana. Berlin, LIT. Friesen, J. (2008). Regional vegetation water effects on satellite soil moisture estimations for West Africa. Bonn, ZEF. Fuest, V. (2006). Demand-oriented Community Water Supply in Ghana. Policies,
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Practices and Outcomes. Berlin, LIT. Laube, W. (2006). Proceedings of the GLOWA Volta Project Workshop "Ghanaian Civil Society: Campaigning and Advocacy within the Water and Mining Sector", 16. October 2006 in Accra/ Ghana. Bonn, GVP. Laube, W. (2007). Changing Natural Resource Regimes in Ghana. Actors, Structures, Institutions. Berlin, LIT. Laube, W. (2007). Changing Resource Regimes in Northern Ghana: Actors, Structures and Institutions. Berlin, Lit. Martin, N. (2006). Development of a water balance for the Atankwidi catchment, West Africa - A case study of groundwater recharge in a semi-arid climate. Göttingen, Cuvillier. Sandwidi, J.-P. W. (2007). Groundwater potential to supply population demand within the Kopienga dam basin in Burkina Faso. Schindler, J. (2009). A multi-agent system for simulating land-use and land-cover changes in the Atankwidi catchment in Upper Eastern Ghana. Bonn.
4.4 Book Sections
Afari-Sefa, V. and S. Bauer (2007). Export Horticulture and Pro-Poor Livelihood Linkages in Southern Ghana: Application of the Agricultural Household Model. Issues and Challenges in Rural Development - Compendium of Approaches for Socio-economic and Ecological Development. Weikersheim/ Germany, Margraf Publishers. 86. Eguavoen, I. (2008). Knowledge resources (yet) untapped. The challenge of interdisciplinarity and finding one´s place in a complex water research project, Volta River Basin, West Africa. Field Research in Difficult Environments. Methodology as Boundary Work in Development Research. P. Mollinga and C. W. (Eds.). Berlin, Lit: 111-135. Eguavoen, I. and D. Spalthoff (2009). The Right Way to Access? Human right, rural water rights and right-based discourses against the privatization of water in Ghana. Water Politics and Development P. Mollinga, S. Saravanana and A. Bhat (Eds.). Berlin, Lit (Accepted for publication). Gleisberg, K. (2008). Cultivating Fields of Knowledge. The problem of knowledge transfer in field research on land use in Burkina Faso. Fieldwork in Difficult Environments. Methodology as Boundary Work in Development Research. P. Mollinga and C. Wall (Eds.). Berlin, Lit: 69-81. Hauck, J. and E. Youkhana (2010). Why does participation fail? - Histories and continuities of water governance in Northern Ghana. From Community to Consumption: New and Classical Themes in Rural Sociological Research. Rural Sociology and
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Development Series. A. Bonanno, H. Baker, R. Jussaume, Y. Kawamura and M. Shucksmith (Eds.). Bingley, Emerald Publishing. Hendrickx, J. M., S. Hong, et al. (2006). Mapping energy balance fluxes and root zone soil moisture in the White Volta Basin using optical imagery. Proc. SPIE Vol. 6239, 62390Q Targets and Backgrounds XII: Characterization and Representation. W. R. Watkins and D. Clement (Eds.). Landmann, T. and S. Dech (2008). Using biophysical data from satellite remote sensing to map wetlands. Earth Observation Manual on Mapping Wetlands from Space . Laube, W. (2007). Changing the Course of History? Contextualising the Adoption and Implementation of Water Policies in Ghana and South Africa. Water, Politics and Development. P. Mollinga, A. Bhat and S. Subramaniam (Eds.). Berlin, Lit. Laube, W. (forthcoming). Changing the Course of History? Contextualizing the Adoption and Implementation of Water Policies in Ghana and South Africa. Water, Politics and Development. P. Mollinga, A. Bhat and S. V. Saravanan (Eds.). Berlin, LIT. Laube, W. and G. van de Giesen (2006). Ghanaian water law and policy: institutional and hydrological perspectives. Hydrologocal information in water law and policy: current practices and future potential. J. Wallace, P. Wouters and S. Pazvakavambwa (Eds.), Kluwer. Laube, W. and G. van de Giesen (2006). Ghanaian Water Reforms: Institutional and Hydrological Perspectives. Hydrological information in water law and policy: current practice and future potential. J. S. Wallace, P. Wouters and S. Pazavakavambwa(Eds.), Kluwer. Laube, W. and E. Youkhana (2006). Virtueller Wasserhandel und Konflikte um Wasser. Virtueller Wasserhandel - Ein realistisches Konzept zum Umgang mit Wasserarmut in Entwicklungsländern? Bonn, Deutsches Institut für Entwicklungspolitik. Laux, P., H. Kunstmann, et al. (2007). Linking West African Monsoon's onset with atmospheric circulation patterns. IAHS Red Book Series. 113: 40-50. Liebe, J., M. Andreini, et al. (2007). The Small Reservoirs Project: Research to Improve Water Availability and Economic Development in Rural Semi-arid Areas. The Hydropolitics of Africa: A Contemporary Challenge. M. Kittisou, M. Ndulo, M. Nagel and M. Grieco (Eds.), Cambridge Scholars Publishing. Rodgers C., N. van de Giesen, et al. (2007). The GLOWA Volta Project: A Framework for Water Resources Decision-Making and Scientific Capacity Building in a Transnational West African Basin. Integrated Assessment of Water Resources and Global Change: A North-South Analysis. E. T. Craswell, M. Bonell, D. Bossio, S. Demuth and N. V. D. Giesen(Eds.): 295-313. Vlek, P. L. G., Q. B. Le, et al. (forthcoming). Land degradation assessment in sub-Saharan Africa Advances in Soil Science Series 16. R. Lal and et.al. (Eds.). CRC Press.
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Youkhana, E. and A. van Edig (2007). Aufbau lokaler Strukturen im Wassersektor. Anspruch und Wirklichkeit des Wasserreformprozesses am Beispiel der kleinstädtischen Trinkwasserversorgung in Ghana. Lokales Wissen und Entwicklung. S. Mielau and F. Wickl (Eds.), Bad Honnef, Horlemann Verlag.
4.5 Conference Paper
Agayre W., Laube W. & Aduna A. (2008). Irrigation Options in the Changing Environment of the White Volta Basin. Multi-Stakeholder Workshop Report. GVP Workshop. 1-2 April 2008, Bolgatanga/ Ghana. Awo, M. (2008). Aid For Trade-From Concepts to Action Germany. GVP Workshop. 1-2 December 2008, Germany Awo, M. (2009). Powerful Queens, poor Farmers: the case of tomato marketing in Northern Ghana International Journal of Arts and Science conference. 16-19 February 2009, USA. Bhaduri A., Manna U., Barbier E. & Liebe J. (2009). Climate Change and Cooperation in Transboundary Water Sharing: An Application of Stochastic Stackelberg Differential Games. 17-th Annual Conference of the European Association of Environmental and Resource Economists (EAERE). Brunner A. C., Kunstmann H. & Vlek P. L. G. (2009). Impact of climate change on soil erosion in Burkina Faso simulated by MM-5 and WEPP-model (presentation). 7th International Conference of Geomorphology (ANZIAG). 6-11. July 2009, Melbourne/ Australia. Conrad C., Falk U., Hendrickx J. M. & Dech S. (2009). Modelling surface energy fluxes based on multi-temporal remote sensing data at different scales Int. Symposium on Remote Sensing and Environment. 3-8 May 2009, Stresa/ Italy. Denisovich, I. and S. Shumilov (2009). Analytical Visualization Framework - a visual data processing and knowledge discovery system. GeoViz meeting on Visualization and the Digital City. Hamburg/ Germany. Eguavoen, I. (2008). Drinking water policy, water rights and allocation practice in rural Northern Ghana. 33rd WEDC International Conference “Access to Sanitation and Safe Water: Global Partnerships and Local Actions”. 7.-11. April 2008, Accra/ Ghana. Falk U., Hendrickx J. M. H., Conrad C. & Vlek P. L. G. (2009). Scintillometry, Eddy Covariance and Remote Sensing for Evapotranspiration Mapping in West-Africa. Int. Symposium on Remote Sensing and Environment. 3-8 May 2009, Stresa/ Italy.
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Friesen, J. and N. v. d. Giesen (2008). Hydrotopes and large scale soil moisture campaigns. AGU Fall meeting. Gleisberg K., Le Q. B. & Vlek P. L. G. (2008). Assessment of the impacts of a small reservoir on land use and livelihood in Burkina Faso. Poster presented International Conference Global Change and Water Resources in West Africa – The German – African GLOWA Projects. 25.-28. August 2008, Ouagadougou/ Burkina Faso. Hauck, J. (2009). Integrating local and scientific knowledge to explain varying fish production of three small reservoirs in northern Ghana Inter- and Transdisciplinary Research on Sustainable Resource Use - Experiences, Methods & Instruments workshop, Helmholtz Centre for Environmental Research – UFZ. January, Leipzig/ Germany. Hauck, J. and E. Youkhana (2008). Histories of water and Fisheries Management in Ghana (paper) XII. World Congress on Rural Sociology. 06.-11. July 2008, Goyang/ Korea. Kasei R., Diekkrüger B., Vlek P. & Leemhuis C. (2008). Drought Frequency in the Volta Basin of West Africa, A Pattern of Climate Change? UNESCO EURO-FRIEND International Workshop on Low Flow and Drought. 10.-12. November 2008, Bratislava/ Slovakia. Kasei R., Diekkrüger B., Vlek P. & Leemhuis C. (2008). Drought Frequency in the Volta Basin of West Africa, A Pattern or Climate Change? Internacional Conference "Water in Africa: Hydro-Pessimism or Hydro-Optimism?" 2- 3 October 2008 , Fundação Eng. António de Almeida – Porto/ Portugal. Kasei R., Diekkrüger B., Vlek P. & Leemhuis C. (2009). Drought Frequency in the Volta Basin of West Africa. Fifth EGU Alexander von Humboldt International Conference. 9-18 January 2009, University of Cape Town Cape Town/ South Africa Landmann T., Machwitz M., Le Q. B., Desta L., Vlek P., Dech S. & Schmidt M. (2008). A land cover change synthesis study for the GLOWA Volta Basin in West Africa using time trajectory satellite observations and cellular automation models. IGARSS. 06.-11. July 2008, Boston/ USA. Landmann T., Machwitz M., Le Q. B., Tamene L. D., Vlek P. L. G., Dech S. & Schmidt M. (2008). A land cover change synthesis study for the GLOWA Volta Basin in West Africa using time trajectory satellite observations and cellular automation models. Paper accepted for orall presentation IEEE Geoscience and Remote Sensing Symposium. 6-11 June 2008, Boston/ USA. Laube, W. (2006). Participatory Decision Support System. GLOWA Volta Project Phase III. Inception Meeting and Workshop. 25-26 September 2006, Accra/ Ghana. Laube, W. (2006). Scientific Decision Support for Sustainable Water Use in the Volta Basin: The Role of Civil Society. GVP. 19 September 2006, Accra/ Ghana.
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Laube, W. (2006). The White Volta Initiative of the GLOWA Volta Project. Pump Irrigation in the White Volta Basin. Stakeholder Workshop, GVP. 2 October 2006, Bolgatanga/ Ghana. Laube, W. (2007). Development Options for the Sustainable Use of Land and Shallow Groundwater in the Upper East Region of Ghana. GLOWA Volta Project Overview and Workshop Objectives. 24 September 2007, Bolgatanga/ Ghana. Laube, W. (2007). GLOWA Volta Project: Impact of environmental, climatic and socio-economic change on the water cycle of the Volta Basin “Partner‟s Capacity Needs Assessment” UNU-INRA/GLOWA-Volta Project. 31 May 2007, Accra/ Ghana. Laube, W. (2007). Klima- und Umweltveränderungen: Lokale Anpassungsprozesse im Norden Ghanas. Dies Academicus of the University of Bonn. 23 May 2007, Bonn/ Germany. Laube, W. (2007). Land Degradation and Governance. Perspectives from West Africa Conference of the Parties to the United Nations Convention to Combat Desertification (COP 8). UNCCD. 3-14 September 2007, Madrid/ Spain. Laube, W. (2008). Comparing Different Types of Irrigation in the Ghanaian White Volta Basin: Institutional, Socio-Economic and Agricultural Aspects. "Irrigation Options in the Changing Environment of the White Volta Basin” GLOWA Volta Project, Multi-Stakeholder Workshop. 1-2 April 2008, Bolgatanga/ Ghana. Laube, W. (2008). Decision Support for Polycentric Water Governance in the Volta Basin. "Global Change and Water Resources in Africa: The German-African GLOWA Projects”. BMBF. 25.-28August 2008, Ouagadougou/ Burkina Faso. Laube, W. (2008). Erratic Rains, Erratic Markets: Limits for local adaptation towards environmental change in northern Ghana. 13th World Water Congress. IWHA. 1-4 September 2008, Montpellier/ France. Laube, W. (2008). GLOWA Volta Project Overview. Bringing the Global Perspective to River Basin Research and Management” GWSP, Global Catchment Initiative: 1st Expert Group Meeting. 7-8 February 2008, Bonn/ Germany. Laube, W. (2008). The GLOWA Volta Project: Impact of environmental, climatic and socio-economic change on the water cycle of the Volta Basin. National Dialogue on Dams and Development in Ghana. 2nd Ghana Dams Forum. February 27 2008, Accra/ Ghana. Laube, W. (2008). Local adaptation towards environmental change in the Atankwidi Basin, northern Ghana. "Frontiers and Passages" Vereinigung der Afrikanisten Deutschlands. 14-17 May 2008, Freiburg i.Br. and Basel, Germany and Switzerland.
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Laube W., Awo M. & Schraven B. (2008). Klimawandel in West-Afrika: Fallbeispiel flussnahe Kleinstbewässerungslandwirtschaft in Nord-Ghana als lokaler Anpassungsprozess. Annual Convention to Combat Desertification (CCD) - Network conference „Nachhaltige Landnutzung angesichts von Klimawandel und UNCCD-Reformprozessen“. 18-19 August 2008, Bonn/ Germany. Laube, W. and Q. B. Le (2007). Development Options for the Sustainable Use of Land and Shallow Groundwater in Atankiri and Anayere catchments (Upper East Region of Ghana). Farmer Workshop Report. GLOWA-Volta Project. 20/22 July 2007, Narvongo/ Ghana. Laube W., Le Q. B. & Agyare W. (2007). Development Options for the Sustainable Use of Land and Shallow Groundwater in the Upper East Region of Ghana. Multi-stakeholder Workshop Report. GLOWA-VOLTA Project. 24 July, Bolgatanga/ Ghana. Laube W., Leemhuis C. & Amisigo B. (2008). Knowledge Exchange within a Multi-Stakeholder Forum: Assessing Climate Change Impact on the Bui Dam for the „Ghana Dam Dialogue‟ Global Change and Water Resources in Africa: The German-African GLOWA projects. 25.-28. August 2008, Ouagadougou/ Burkina Faso. Laube W., Mdemu M., Awo M., Schraven B. & Gensler M. (2008). Irrigation Systems in the White Volta Basin: Institutional Framework, Socio-Economic Impact and Adaptation to Environmental Change. Global Change and Water Resources in Africa: The German-African GLOWA projects. 25.-28. August 2008, Ouagadougou/ Burkina Faso. Laube W., Schraven B. & Awo M. (2008). Climatic and Environmental Change in Northern Ghana: Local Adaptation Via Shallow Groundwater Irrigation (SGI). Global Change and Water Resources in Africa: The German-African GLOWA projects. 25.-28. August 2008, Ouagadougou/ Burkina Faso. Laube, W. and D. Spalthoff (2006). Proceedings of the GVP-Workshop „Ghanaian Civil Society: Campaigning and Advocacy with in the Water and Mining Sector‟. GVP. 16 October 2006, Accra/ Ghana. Laube, W. and E. Youkhana (2006). Virtual water Trade: political and social challenges in West Africa International Workshop Governance and the Global Water System: Institutions, actors, and scales of water governance facing the challenges of global change. GWSP. 20-23 June 2006 , Bonn/ Germany. Laube W., Youkhana E., Eguavoen I., Edig A. v., Fuest V., Schaaf C. v. d., Awo M., Derbile E., Gensler M., Schraven B., Sessouma A. & Spalthoff D.(2008). Polycentric Water Governance in the Volta Basin: Sociological Research and Concepts for Decision Support. Global Change and Water Resources in Africa: The German-African GLOWA projects. 25.-28. August 2008, Ouagadougou/ Burkina Faso. Laux P., Heckl A., Jacobeit J., Bárdossy A. & Kunstmann H. (2008). Linking droughty and wet weather in the Jordan region with atmospheric circulation patterns. AEC conference 8.-11. October 2008, Tarragona/ Spain.
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Laux, P., Jäckel, G., Tingem, M., Kunstmann, H. (2009). Onset of the rainy season and crop yield in Sub Saharan Africa - Tools and perspectives for Cameroon. Joint IAHS & IAH Covention, 6-12 September 2009. Hyderabad/ India. Laux, P. and H. Kunstmann (2006). Analysis of the monsoon onset in the Volta basin (West Africa). EGU General Assembly. 02.-07. April 2006, Vienna/ Austria. Laux P., Kunstmann H., Lutz K., Jacobeit J., Beck C., Philipp A. & Bárdossy A. (2008). Comparison of different objective atmospheric circulation pattern analyses in the Jordan region (paper). HydroPredict. 15.-18. September 2008, Prague/ Czech Republic. Le Q. B., Schindler J., Gleisberg K., Laube W., Tamene L. & Vlek P. L. G. (2008). A multi-agent based decision support tool for the management of land and water resources of small catchments in the Volta River basin. Oral presentation at the International Conference Global Change and Water Resources in West Africa – The German – African GLOWA Projects. 25 – 28August 2008, Ouagadougou/ Burkina Faso. Le Q. B., Tamene L. & Vlek P. L. G. (2008). Anthropogenic land degradation in Volta basin from 1982 to 2003 in the background of global change in atmospheric chemistry. Poster presented International Conference Global Change and Water Resources in West Africa – The German – African GLOWA Projects. 25 – 28 August 2008, Ouagadougou/ Burkina Faso. Leemhuis C., Jung G., Kasei R., Perez N., Bhaduri A. & Liebe J. (2009). Socio-economic water resources impact assessment in Sub-Saharan Africa: The M³ WATER model for the Volta Basin. 1. Mike Anwendertreffen. 28.-29. April 2009, Cologne/ Germany. Leemhuis C., Jung G., R. K. & Liebe J. (2009). Reservoir impact assessment in sub-Saharan Africa: The Volta Basin Water Allocation System (VB-WAS) (poster). EGU, General Assembly. 19.-24. April 2009, Vienna/ Austria. Machwitz M., Falk U., Richters J., Conrad C. & Dech S. (2009). Modeling the carbon budget at regional scale in West Africa using 250 m MODIS data and ground observations. ISRSE 2009. Stresa/ Italy. Machwitz M., Falk U., Richters J., Conrad C. & Dech S. (2009). Remote Sensing of Environment Modelling the Carbon Budget at regional scale in West Africa using 250 m MODIS data and ground observations Int. Symposium on Remote Sensing and Environment. 3-8 May 2009, Stresa/ Italy. Machwitz M., Kasei R., Falk U., Richters J., Conrad C. & Dech S. (2009). Modelling Net Primary Productivity at regional scale in West Africa using 250 m MODIS data and different climate data – a comparison. Carbon Dioxide Conference Jena/ Germany. Machwitz M., Landmann T., Conrad C., Cord A. & Dech S. (2008). Land cover analysis on sub-continental scale: FAO LCCS standard with 250 meter MODIS satellite observations in West Africa. IGARSS. 06.-11. July 2008, Boston/ USA.
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Obuobie, E. and B. Diekkrueger (2009). Climate Change Impact on Hydrology and Water Resources in the White Volta River Basin, West Africa. 5th International SWAT Conference. 03.-04. August 2009, Boulder/ USA. Obuobie E., Diekkrueger B. & Liebe J. (2009). Impact of Climate Change on River Discharge in the White Volta River Basin, West Africa. IMPETUS International Conference “Global Change in Africa". 02.-04. June 2009, Cologne/ Germany. Schindler J., Le Q. B., Laube W. & Vlek P. L. G. (2008). Simulation of policy-based scenarios for land-use and land-cover change and income in Atankwidi (Ghana). Poster presented International Conference Global Change and Water Resources in West Africa – The German – African GLOWA Projects. 25 – 28 August 2008, Ouagadougou/ Burkina Faso. Schindler J., Le Q. B., Laube W. & Vlek P. L. G. (2009). A multi-agent system for simulating land-use and land-cover change in Atankwidi catchment of Upper East Ghana. Poster presented International Conference “Global Change and Water Resources in West Africa – The German – African GLOWA Projects. 25 – 28August 2008, Ouagadougou/ Burkina Faso. Schraven, B. (2008). Klimawandel in West-Afrika: Kleinstbewässerungslandwirtschaft in Nord-Ghana als lokaler Anpassungsprozess. Annual Convention to Combat Desertification (CCD) - Network conference „Nachhaltige Landnutzung angesichts von Klimawandel und UNCCD-Reformprozessen“. 18.-19. August 2008, Bonn/ Germany. Tamene L., Le Q. B. & Vlek P. L. G. (2008). Anthropogenic land degradation in the Volta basin from 1982 to 2003. Poster presented International Conference Global Change and Water Resources in West Africa – The German – African GLOWA Projects. 25 – 28 August 2008, Ouagadougou/ Burkina Faso. van de Giesen N., Andah W., Andreini M., Barry B., Jung G., Kunstmann H., Laube W., Laux P. & Liebe J. (2008). Adapting to Climate Change in West Africa. Expo Zaragoza/ Spain. Vlek P. L. G., Perez N., Bhaduri A., Leemhuis C., Denisovich I., Savinov A. & Liebe J. (2009). The M³ WATER Model for the Volta Basin: Hydro-economic water resources assessment in Sub-Saharan Africa. IHDP Open Science meeting. Bonn/ Germany. Wagner S., Kunstmann H. & Bárdossy A.(2008). Propagation of precipitation uncertainties in water balance estimations (poster). European Geosciences Assembly General Assembly. 13.-18. April 2008, Vienna/ Austria. Wagner S., Kunstmann H. & Bárdossy A. (2008). Propagation of precipitation uncertainties in distributed water balance assessments of a data sparse semi arid environment (paper). Hydro Predict. 15.-18. September 2008, Prague/ Czech Republic. Wagner S., Kunstmann H. & Bárdossy A. (2009). Uncertainty assessment of hydrological predictions due to sparse precipitation stations. IAHS 8th Scientific Assembly. 06.-12. September 2009, Hyderabad/ India.
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4.6 Conference Proceedings – Presentations and Posters
Abukari M., Hauck J. & Schiffer E. (2007). Influence Network Mapping, A Tool to Understand how People use Small Reservoirs, Feedback from Field Testing (presentation). IFAD Knowledge Profiling Workshop, July 2007, Tamale/ Ghana. Afari-Sefa, V. (2006). The Interlinks between Agricultural Export Diversification, Food Security and Livelihood of Farm Households in Southern Ghana. Ninth Annual Conference on Global Economic Analysis/ UNECA 15.-17. June 2006, Addis Ababa/ Ethiopia. Afari-Sefa, V. (2007). The Distributional Effects of Horticultural Export Value Chains Among Smallholders in Southern Ghana (presentation). Second International Conference of the Association of Agricultural Economists (AAAE), 20.-22. August 2007, Accra/ Ghana. Afari-Sefa V., Rodgers C., Plotnikova M. & Vlek P. (2007). The Implications of Increasing Water Demand and Potential Climate Change in the Volta Basin for Ghana's Socio-Economic Development (presentation). World Water Week, 12.-18. August 2007, Stockholm/ Sweden. Alamirew, D. (2007). Application of SWAT for assessment of spatial distribution of water resources and analyzing impact of different land management practices on soil erosion in Upper Awash River Basin watershed (presentation). Workshop on Integrated Watershed Management and Sanitation, May 2007, Ethiopia. Barbier, B. (2006). Gestion de l'eau dans le bassin de la Volta : optimisation dynamique et récursive. Conférence internationale "Mathématiques et problèmes de dévelopement au Sahel", Ouagadougou, Burkina Faso. Bhaduri A., Amarasinghe U. A. & Shah T. (2008). Benefits of Irrigation Water Transfers in the National River Linking Project: A Case Study of Godavari (Polavaram)-Krishna Link in Andhra Pradesh in Amarasinghe, U.A. . Strategic analyses of the National River Linking Project. of India . Workshop on Analyses of Hydrological, Social and Ecological Issues of the NRLP, International Water Management Institute, Colombo/ Sri Lanka. Bhaduri, A. and E. Barbier (2008). In the Ganges-Brahmaputra River Basin: Exploring the Transboundary Effects in Amarasinghe, U.A Strategic analyses of the National River Linking Project (NRLP) of India, series 2. Proceedings of the Workshop on Analyses of. Hydrological, Social and Ecological Issues of the NRLP, International Water Management Institute, Colombo/ Sri Lanka. Brunner A., Vielhauer K. & Vlek P. L. G. (2006). Dammed-up problems: challenges and difficulties in small-holder irrigation agriculture in south-western Burkina Faso (poster). Tropentag, 11.-13. October 2006, Bonn/ Germany.
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Brunner, A. C. and P. L. G. Vlek (2008). Impact of climate change on soil redistribution pattern along transects in Burkina Faso simulated by the Water Erosion Prediction Project (WEPP)-model (presentation). ISCO-Conference "Soil and Water Conservation, Climate Change and Environmental Sensitivity", Budapest/ Hungary. Codjoe, S. (2006). Effects in Changes in Population, Household Conditions, and Farming Systems on Agricultural Land Use in the Volta River Basin of Ghana, 1984-2000 (poster). Tropentag, 11.-13. October 2006, Bonn. Conrad C., Falk U., Hendrickx J. M. & Dech S. (2009). Modelling surface energy fluxes based on multi-temporal remote sensing data at different scales (poster). Int. Symposium on Remote Sensing and Environment, 3-8 May 2009, Stresa, Italy. Eguavoen, I. (2006). Drinking Water Policy, Water Rights and Allocation Practice in Rural Northern Ghana (presentation). Tropentag, 11.-13. October 2006, Bonn. Eguavoen, I. (2007). Household water supply, water rights and institutional change in Northern Ghana (presentation). 5th IWHA Conference (International Water History Association), 13.-17. June 2007, Tampere/ Finland. Eguavoen, I. (2008). Decision Support for the Drinking Water Sector (poster). Global Change and Water Resources in Africa: The German-African GLOWA projects, 25.-28. August 2008, Ouagadougou/ Burkina Faso. Eguavoen, I. (2008). Drinking water policy, and allocation practice in rural Northern Ghana (presentation). 33rd WEDC International Conference, 7.-11. April 2008, Accra/ Ghana. Eguavoen, I. and D. Spalthoff (2008). Getting Access Right: Human rights and household water rights in Ghana (presentation). XIIIth World Water Congress, Montpellier/ France, 1.-4. September 2008. Eguavoen, I. (2009). Shifting perceptions. Environmental policy and research in Northern Ghana (presentation). World Conference on Environmental History. Copenhagen/ Denmark. Elgayyar, M., Leng, Y., Shumilov, S. , Cremers, A.B. (2009). New Execution Paradigm for Data Intensive Scientific Workflows. 3rd IEEE International Workshop on Scientific Workflows . 10 July 2009, Los Angeles, USA. Elgayyar M. M., Alda S. J. & Cremers A. B. (2008). Towards a user-oriented environment for web services composition. 4th international Workshop on End-User Software Engineering, Leipzig/ Germany, 12 May 2008, New York, NY/USA. Frazier, T. (2009). A Comprehensive Energy Use Plan for Greater Accra, Ghana (presentation). March 2009, Kwame Nkrumah University of Science and Technology (KNUST); Kumasi/ Ghana.
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Frazier, T. (2009). Powering Accra: Projecting Electricity Demand for Ghana‟s capital city (presentation). July 2009, Swiss Federal Institute of Technology, Zurich/ Switzerland. Friesen, J. (2007). Elastic Stem Measurements of Above Ground Tree Mass Change (poster and presentation). EGU General Assembly, 15.-20. April 2007, Vienna/ Austria. Friesen, J. (2007). Spatial and seasonal patterns of diurnal differences in ERS Scatterometer soil moisture data in the Volta Basin, West Africa (presentation). XXIV IUGG General Assembly, 9.-13. July 2007, Perugia/ Italy. Friesen, J. (2007). Weighing trees: Measuring interception and evaporation dynamics by monitoring sub-micrometer tree trunk compaction (presentation). AGU 2007 Fall Meeting, 10.-15. December 2007, San Francisco, USA. Friesen, J. and N. v. d. Giesen (2009). Diurnal differences in ERS scatterometer backscatter for West Africa (poster) EGU General Assembly 2009, 19.-24. April 2009, Vienna/ Austria. Gleisberg K., Arntz C. & Le Q. B. (2008). Integrated assessment of the impact of a small reservoir on land use and livelihood in Burkina Faso (presentation). 13th IWRA World Water Congress: Global Changes and Water Resources, 1.-4. September 2008, Montpellier/ France. Hauck, J. (2008). Fisheries in Small Reservoirs: Incidental Benefit or Important Livelihood Strategy? (paper) Irrigation Options in the Changing Environment of the White Volta Basin Workshop, Bolgatanga/ Ghana, April. Hauck, J. and E. Youkhana (2008). Claim and reality of community based water management (presentation). XII World Congress of Rural Sociology, 6.-11. July 2008, Goyang/ Korea. Heckl. A and P. Laux (2008). High resolution climate scenarios in the Near East (poster and presentation). GLOWA Jordan Status Conference, 25-27June 2008, Aqaba/ Jordan, . Jäckel G., Laux P., Tingem M. & Kunstmann K. (2009). Onset of the rainy season and crop yield in Sub Saharan Africa - Tools and perspectives for Cameroon (poster). EGU 2009, 20-24April 2009, Vienna/ Austria. Jung, G. and K. H. (2007). Modelling regional climate change and the impact on surface and sub-surface hydrology in the Volta Basin (West Africa). Quantification and Reduction of Predictive Uncertainty for Sustainable Water Resources Management. Proceedings of Symposium HS2004, IUGG, July 2007, Perugia/ Italy. Kafando A., Barbier B., Benoît-Cattin M. & Ruas J.-F. (2006). Simulation à long terme de la sécurité alimentaire au Sahel. Conférence internationale "Mathématiques et problèmes de dévelopement au Sahel", Ouagadougou/ Burkina Faso.
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Kasei, R. (2007). GVP Hydro-Meteorological Data: Collection, Storage & Management (presentation). United Nationa University Workshop "Capacity Building and Data Management", 26.-29. September 2007, Accra/ Ghana. Kasei, R. (2009). (presentation). Fifth EGU Alexander von Humboldt International Conference, 9-18 January 2009, University of Cape Town Cape Town/ South Africa. Kpongor, D. S. (2008). (presentation). International Crop Science Conference, 13.-18. April 2008, Jeju/ Korea. Kpongor D. S., Sommer R. & Vlek P. L. G. (2006). Modeling Sorghum Yield in Response to inorganic fertilizer application in semi-arid Ghana (poster). Tropentag, 11-13. October 2006, Bonn/ Germany. Landmann, T. (2006). Long term global monitoring of vegetation variables using moderate resolution satellites (poster). A combined meeting of the third biennial global vegetation workshop at the University of Montana and the Committee on Earth Observing Satellites Working Group on Calibration and Validation, 07.-10. August 2006., Montana/ USA. Landmann T., Colditz R. R., S.W.Dech & Schmidt M. (2007). A Land Cover Classification System (LCCS) Based Wetland Biodiversity Characterization Method for West African Savannas Using 250-meter MODIS Observations. 32nd International Symposium on Remote Sensing of Environment: "Sustainable Development through Global Earth Observations", San Jose/ Costa Rica. Landmann T., Herty C., Dech S., Schmidt M. & Vlek P. (2007). Land cover change analysis within the GLOWA Volta basin in West Africa using 30-meter Landsat data snapshots. GARSS 2007. IEEE International Conference, Barcelona/ Spain. Landmann T., Machwitz M., Le Q. B., Tamene L. D., Vlek P. L. G., Dech S. & Schmidt M. (2008). A land cover change synthesis study for the GLOWA Volta Basin in West Africa using time trajectory satellite observations and cellular automation models (presentation). IEEE Geoscience and Remote Sensing Symposium, 6.-11. June 2008, Boston, MA/ USA. Landmann T., Vlek P. L. G., Schmidt M., Dech S. & Cord A. (2007). An object-conditional approach for satellite remote sensing land cover mapping in African Savannas. Third International Workshop; Image Fusion and Geographic Information Systems, 21.-25. May 2007, St Petersburg/ Russia. Laube, W. (2006). Participatory Decision Support System (presentation). GLOWA Volta Phase III Inception Workshop, 25.-26. September 2006, Accra/ Ghana. Laube, W. (2006). The White Volta Initiative of the GLOWA Volta Project (presentation). GLOWA Volta Stakeholder Workshop on Pump Irrigation in the White Volta Basin, 2. October 2006, Bolgatanga/ Ghana.
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Laube, W. (2007). The GLOWA Volta Project, Knowledge Sharing and Decision Support (presentation). Negotiation Processes between the State, Civil Society and Communities in the Delivery of (Public) Services, 28. March 2007, Sociology Department of the University of Ghana, Legon, Accra/ Ghana. Laube, W. (2007). GLOWA Volta Project: Sustainable Water Use under Changing Bio-Physical and Socio-economic Conditions in the Volta Basin (poster). Conference of the Parties to the United Nations Convention to Combat Desertification (UNCCD/COP 8), 3.-14. September 2007, Madrid/ Spain. Laube, W. (2007). Governance and Desertification: Examples from the west African Volta Basin (presentation). Conference of the Parties to the United Nations Convention to Combat Desertification (UNCCD/COP 8), 3.-14. September 2007, Madrid/ Spain. Laube, W. (2007). Klimawandel und Umweltveränderungen: Lokale Anpassungsprozesse im Norden Ghanas (presentation), Dies Academicus 23. May 2007, University of Bonn/ Germany. Laube, W. and Q. B. Le (2007). Development Options for the sustainable use of land and shallow groundwater in Atankiri and Anayere catchments (Upper East Region of Ghana). Report. GVP Farmer Workshops, 20.-22. July 2007, Navrongo/ Ghana. Laube W., Schraven B. & Sebaly C. (2007). Local adaptation to Climate Change: Farmer-Driven Irrigation Development in the White Volta Basin (poster). Conference of the Parties to the United Nations Convention to Combat Desertification (UNCCD/COP 8), 3.-14. September 2007, Madrid/ Spain. Laube, W. and T. Stellmacher (2006). Land Degradation and Governance Perspectives from West Africa (presentation prepared for Prof. S. Gerke). UNCCD and University of Bonn Joint Workshop "Widening the bridge between research and action", 28. November 2006, Bonn/ Germany. Laube, W. and E. Youkhana. (2006). Virtual water Trade: political and social challenges in West Africa (presentation). International Workshop Governance and the Global Water System: Institutions, actors, and scales of water governance facing the challenges of global change. 20.-23. June 2006, Bonn/ Germany. Laux, P. (2007). Analyse täglicher Niederschlagszeitreihen zur Ableitung einer landwirtschaftlichen Entscheidungsunterstützung im Volta Becken (West-Afrika) (presentation). Geographical Colloquium University of Augsburg, 26 November 2007, Augsburg/ Germany. Laux, P. (2009). Global climate change and its regional agricultural and hydrological impacts for West Africa: Challenges and opportunities for a German-Nigerian collaboration (presentation). Lagos Maiden Summit on Global Climate Change 2009, 23-27 March 2009, Lagos/ Nigeria.
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Laux, P., Kunstmann, et al. (2008). Predicting the regional onset of the rainy season in West Africa (poster and presentation). Status Conference GLOWA Volta 2008, 24-26August 2008. Laux P., Kunstmann H. & Bárdossy A. (2007). Linking the West African monsoon's onset with atmospheric circulation patterns (presentation). IUGG Conference, 2.-13. July 2007, Perugia/ Italy. Laux P., Kunstmann H. & Bárdossy A. (2007). Stochastic rainfall simulation for the Volta Basin in West Africa (poster). 2nd international AMMA Conference, 26.-30. November 2007, Karlsruhe/ Germany. Laux P., Kunstmann H. & Bárdossy A. (2008). Assessing the Impact of Climate Change on the Frequency of Droughty and Wet Weather Patterns in the Volta Basin (poster). Status Conference GLOWA Volta 2008, 24-26 August 2008. Laux P., Kunstmann H. & Bárdossy A. (2008). Modelling Daily Precipitation Features for Agricultural Decision Support in the Volta Basin (poster). Status Conference GLOWA Volta 2008, 24-26.August Laux P., Yang W., Kunstmann H. & Bárdossy A. (2007). Stochastic rainfall simulation for the rainy season of the Volta Basin in West Africa (poster). EGU, 15.-20. April 2007, Vienna/ Austria. Le Q. B., Park S. J. & Vlek P. L. G. (2007). A multi-agent system model for simulating spatio-temporal dynamics of coupled human-landscape system in forest margins: conceptual framework and theoretical application. International Conference "Framing Land Use Dynamics II, 18.-20. April 2007, Utrecht/ The Netherlands. Le, Q. B. and L. Tamene (2006). A multi-agent-based approach to support micro-catchments land/water management planning in the Volta Basin (paper). Conference on Integrated water resources management in contrasting climate zones, 14.-15. December 2006, University of Hohenheim/ Germany. Le Q. B., Tamene L. D., Landman T., Rodgers C. & Vlek P. L. G. (2007). A cellular automata approach to simulating land-use/land-cover changes in the White Volta basin. International Conference "Framing Land Use Dynamics II", 18.-20. April 2007, Utrecht/ The Netherlands. Leemhuis, C. (2008). (presentation). The role of hydrology in water resources management, 13.-16. October 2008, Naples/ Italy. Machwitz M., Schramm M., Landmann T. & Dech S. (2008). Remote sensing based determination of the percentage tree cover in West Africa. European Geosciences Union General Assembly, 13-18 April 2008, Vienna/ Austria, . Mandé, T. and B. Barbier (2006). Un modèle d'optimisation stochastique d'un ménage sahélien. Conférence internationale "Mathématiques et problèmes de dévelopement au Sahel", Ouagadougou/ Burkina Faso.
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Mandé T., Barbier B., Compaoré L., Karambiri H. & Hama Y. (2007). Is small scale irrigation a valuable recourse to climate variability in the Sahel? Economic stochastic programming at the farm level. AMMA Conference, Karlsruhe/ Germany. Martin, N., I. Eguavoen, et al. (2007). Hydrogeological and Socio-Legal Aspects of Groundwater for Household Provision in the Volta River Basin. Tropentage, 9 – 11 October 2007, Witzenhausen/ Germany. Martin N., Eguavoen I., Sandwidi J.-P. & Sessouma A. (2007). Hydrogeological and socio-legal aspects of groundwater for household provision in the Volta River Basin (poster). Tropentag, 09.-11. October 2007, Witzenhausen/ Germany. Martin, N., I. Eguavoen, et al. (2008). Aspects hydrogéologiques et socio-legaux des eaux souterraines dans la satisfaction des besoins domestiques au niveau du bassin versant de la Volta (poster). XIIIth World Water Congress, 1.-4. September 2008, Montpellier/ France. Mdemu, M. V. (2009). Temporal Water Productivity of Tomato in Reservoir and Hand-dug-well Dry Season Irrigated Plots in the Upper East Region, Ghana (accepted abstract). Tropentag 2009, 14-16 September 2010, Zurich/ Switzerland. Moene A. F., Bruin H. A. R. d. & Schuttemeyer D. (2007). The effect of surface heterogeneity on the temperature-humidity correlation and the relative transport efficiency. Geophysical Research Abstracts of the European Geosciences Union General Assembly, 15.-20. April 2007, Vienna/ Austria. Moene A. F., Schüttemeyer D. & Hartogensis O. K. (2006). Scalar similarity functions: the influence of surface heterogeneity and entrainment. The 17th Symposium on Boundary Layers and Turbulence. Moene A. F., Bruin H. A. R. d. & Schuttemeyer D. (2007). Basin-wide, year-round estimation of actual evaporation for the Volta Basin using remote sensing. Geophysical Research Abstracts of the European Geosciences Union General Assembly, 15.-20. April 2007, Vienna/ Austria. Nyarko, B. K. (2006). Modeling floodplain extent in the White Volta Basin: an application of the lisflood-FP model (poster). EGU General Assembly, 02.-07. April 2006, Vienna/ Austria. Nyarko, B. K. (2008). (presentation). Annual meeting of Society for Wetland Scientists, 26.-30. May 2006, Washington, D.C/ USA. Nyarko, B. K. (2008). (presentation). Association of American Geographers Annual Meeting, 15.-18. April 2008, Boston, Massachusetts/ USA. Nyarko B. K., Diekrüger B., van de Giesen N. & Rodgers C. (2007). Modeling unsaturated zone of floodplain wetlands in the White Volta basin, Ghana (poster). EGU General Assembly, 16.-20. April 2007, Vienna/ Austria.
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Nyarko B. K., Diekrüger B., van de Giesen N. & Vlek P. L. G. (2007). Floodplain Wetland Mapping for Environmental flow assessment in the White Volta Basin. UN/ Morroco/ ESA international workshop on Use of Space Technology for Sustainable Development, 25.-27. April 2007, Rabat/ Morocco. Nyarko B. K., Reichert B., van de Giesen N. & Vlek P. L. G. (2007). Use of Isotope to study Floodplain-Wetland and Rivers Flow interaction in the White Volta Basin, Ghana. Society for Wetland Scientist Annual Conference, 10.-15. June 2007, Sacramento/ USA. Obuobie, E. (2008). (presentation). Tropentag 7.-9. October 2008, Stuttgart/ Germany. Obuobie, E. (2008). (presentation). International SWAT Conference., 17.-19. October 2008, Beijing/ China. Perez, N. (2008). (presentation). EcoMod2008 Conference, 2.-4. July 2008, Berlin/ Germany. Rogmann, A. (2007). Data Management in the GLOWA Volta Project. Data Management and Application of GIS and Remote Sensing in Natural Resources Management Training Workshop, 12-14 December 2007, Ouagadougou/ Burkina Faso. Rogmann, A. (2007). Data Management in the GVP. Phase III Strategy and Planning Meeting, 22 - 23January 2007, Bonn-Röttgen/ Germany. Rogmann, A. (2007). Geodatabase in the GLOWA-Volta Project. Geodatabase Workshop. ZEF, 18 September 2007, Bonn/ Germany Rogmann, A. (2007). GVP Geo-Portal and Access to Project Data (presentation). Partners Capacity Needs Assessment Workshop, May 31st – June 1st 2007, Accra/ Ghana. Rogmann, A. and S. Shumilov (2008). The GLOWA Volta Geoportal an Inter-active Geodata Repository and Communication System (presentation). GLOWA Volta Status Conference, 25-28 August 2008, Ouagadougou/ Burkina Faso. Rogmann, A. and S. Shumilov (2008). Results of the Survey “GLOWA Volta Data Questionnaire” / Data Management at the water sector in Ghana and Burkina Faso Descriptive documentation (14 S.) linked with reports generated from survey result database, 1 January 2008, Accra/ Ghana and 14 December 2008, Ouagadougou/ Burkina Faso. Rogmann, A. and S. Shumilov (2008). Enterprise Data Management, Distribution and Meta Data Catalogue System (Poster). GLOWA Volta Status Conference, 25-28 August 2008, Ouagadougou/ Burkina Faso Sandwidi, J.-P. (2008). Long-term balance between domestic water demand and groundwater recharge of the crystalline basement aquifers in the Northern Volta river basin, West Africa (presentation). EGU, Vienna/ Austria
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Sandwidi J.-P., Giesen N. v. d. & Rodgers C. (2007). Flow processes in groundwater recharge to a crystalline basement aquifer in a semi-arid West African river basin (presentation). EGU General Assembly, 16.-20. April 2007, Vienna/ Austria. Sandwidi J. P., van de Giesen N., Rodgers C., Bogardi J. J. & Vlek P. L. G. (2006). Groundwater Potential Assessment in Kompienga dam basin using multiple methods (poster). Tropentag, 11.-13. October 2006, Bonn/ Germany. Sanfo S., Kaboré M., Barbier B. & Mandé T. (2008). Irrigation formelle et informelle pour la production de contre-saison au Burkina Faso : réalité statistique et potentiel de développement. Irrigation informelle : Importance et perspective en Afrique de l'Ouest et du centre, 29. January 2008, Ouagadougou/ Burkina Faso. Shumilov S., Leng Y., Elgayyar M. & Cremers A. B. (2008). Distributed Scientific Workflow Management for Data-Intensive Applications. I12th IEEE International Workshop on Future Trends of Distributed Computing Systems (FTDCS 2008), Kunming/ China. Shumilov S., Leng Y., Elgayyar M. & Cremers A. B. (2008). Distributed Scientific Workflow Management for Data-Intensive Applications (paper). 12th IEEE International Workshop on Future Trends of Distributed Computing Systems, 21.-23. October 2008, Kunming/ China. Shumilov, S. and A. Savinov (2008). Grid-Based Infrastructure for the GLOWA Volta Decision Support System (poster). International Conference Global Change and Water Resources in West Africa, 25-29 August 2008, Ouagadougou/ Burkina Faso. Spalthoff D., Van-Rooijen D. J. & Raschid-Sally. L. (2008). Domestic Water Supply in Accra: how physical and social constraints to planning have greater consequences for the poor (presentation). 33rd WEDC International Conference, 1.-4. April 2008, Accra/ Ghana. Szarzynski, J. (2006). Possible cooperations with existing scientific networks in West Africa (BIOTA West Africa / GLOWA Volta) (presentation). WWRP/ THORPEX Health Application Workshop on Forecasting adverse health impacts in Africa. World Meteorological Organization (WMO), 03.-07 April 2006, Geneva/ Switzerland. Szarzynski, J. (2007). Application of ground-based and airborne infra-red thermography for environmental monitoring. International Congress on Modelling and Simulation (MODSIM07). Land, Water and Environmental Management: Integrated Systems for Sustainability. 10.-13. December 2007, University of Canterbury, Christchurch/ New Zealand. Szarzynski J., Kunstmann H., Falk U., Rodgers C. & Vlek P. L. G. (2007). Monitoring of Climate Variability and Land Cover Changes in support of Human Health Research in West Africa (poster). International Conference-Towards Sustainable Global Health, 09.-11. May 2007, Bonn/ Germany.
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Tamene L., Le Q. B., Liebe J. & Vlek P. L. G. (2009). Developing a decision support tool for landscape planning and management to minimize land and water degradation in Volta basin (poster). European Geosciences Union (EGU) General Assembly 2009, (Session: Geomorphology (GM), Sub-session: Environmental Change in Sub-Saharan Africa (CL61/GM3.6/SSP12)). 19-24 April 2009. Tia L., Schmidtlein S. & Vlek P. L. G. (2007). Estimating and upscaling tree density by applying LAI-SEB Model to optical remotely sensed imagery within the Volta Basin (West Africa) (poster). Tropentag, 9.-11. October 2007, Witzenhausen/ Germany, . Tsegai, D. (2006). Migration Dynamics in Ghana - Implications for Migration Forecast (poster). Tropentag, 11.-13. October 2006, Bonn. Vielhauer, K. (2006). Linking Research and Develompent in Southwestern Burkina Faso (poster). Tropentag, 11.-13. October 2006, Bonn/ Germany. Vielhauer K., Fosu B. Y., Vlek P. L. G. & Manske G. (2006). The use of Azolla to increase N fertilizer use efficiency in lowland rice in Dano, Southwestern Burkina Faso (poster). Tropentag, 11-13 October 2006, Bonn/Germany. Vlek P. L. G., Le Q. B. & Tamene L. (2009). African land degradation in a world of global atmospheric change: atmospheric fertilization conceals degradation? (Poster presentation). European Geosciences Union (EGU) General Assembly 2009 (Session: Biogeosciences (BG), Sub-session: Impact of atmospheric nitrogen deposition on terrestrial carbon balance (BG2.5)). 19-24 April 2009. Wagner S., Kunstmann H. & Bárdossy A. (2007). Uncertainties in water balance estimations due to scarce meteorological information: a case study for the White Volta catchment in West Africa (poster). IUGG Conference, July 2007, Perugia/ Italy. Wagner S., Kunstmann H. & Bárdossy A. (2007). Uncertainties in water balance estimations due to scarce meteorological information: A case study for the White Volta catchment in West Africa. Symposium HS2004 at IUGG2007, July 2007, Perugia/ Italy, IAHS Red Book Series. Wagner S., Kunstmann H., Bárdossy A. & Conrad C. (2007). Water balance simulations in a poorly gauged basin using different meteorological and land surface data sources (presentation). EGU, Vienna/ Austria. Wagner S., Kunstmann H., Bárdossy A., Conrad C. & Colditz R. (2007). Water balance estimation in a poorly gauged basin using atmospheric modelling and remote sensing information (presentation). AMMA 2nd International Conference, Karlsruhe/ Germany. Wagner S., Kunstmann H., Laux P. & Jung G. (2006). Instruments for Hydrometeorological Decision Support in Sustainable Water Management (poster). GTZ 1. Expertengespräch: Wasser, Ernährung und Umwelt.
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Wagner S., Laux P., Jung G. & Kunstmann K. (2009). Instruments for Hydrometeorological Decision Support in Sustainable Water Management for the Volta Basin (poster). Status Conference GLOWA Volta 2008, 24-26 August 2009. Winsemius H. C., Friesen J., Szarzynski J. & van de Giesen N. (2006). Radiation and land surface temperature from Meteosat second generation (poster). European Geosciences Union (EGU) General Assembly, 02. - 07. April 2006, Vienna/ Austria. Youkhana, E. and W. Laube (2006). Virtual water trade: political and social challenges in the Volta basin (presentation). GWSP Conference 'International Workshop Governance and the Global Water System: Institutions, actors, and scales of water governance facing the challenges of global change', 20-22June 2006, Bonn/ Germany. Zitzmann, K. and Q. B. Le (2008). Integrated assessment of the impact of a small reservoir on land use and livelihood in Burkina Faso (presentation). 13th IWRA World Water Congress: Global Changes and Water Resources, 1-4 September 2008, Montpellier/ France.
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4.7 Documentation of research
Aidam, P. W. (2006). The Impact of Agricultural Sector Policies on the Demand for Water Resources within the Volta Basin in Ghana, West Africa (PhD proposal). GVP/ ZEF, Bonn. Gensler, M. (2006). Adaptation of new water management institutions in agriculture: The case of small dams in Northern Ghana, paper presented at the researcher-training workshop "Property and Access to Resources", Bornholm/ Denmark, 22.-24.09.2006. Landmann T., Colditz R., Schmidt M. & Dech S. (2006). An Object-Conditional Land Cover Classification System (LCCS) Wetland Probability Detection Method for West African Savannas Using 250-Meter MODIS Observations. In Proc. 'GlobWetland: Looking at Wetlands from Space' (Eds. H. Lacoste), ESA SP-634 (CD-ROM), ESA Publications Division, European Space Agency, Noordwijk/ Netherlands. Landmann T., Schmidt M., Dech S., Vogel M. & Schramm M. (2006). A new spatially-explicit and object-conditional land cover (LC) data set based on the FAO Land Cover Classification System (LCCS) for the GLOWA catchment area, Proceeding of the 6th AARSE international conference on earth observation and geoinformation sciences in support of Africa's development, 30 October - 2 November 2006, Cairo/ Egypt: The National Authority for Remote Sensing and Space Science (NARSS), 2006. ISBN 1-920-01710-0. pp. 144-149. Laube, W. and E. Youkhana (2006). Virtueller Wasserhandel und Konflikte um Wasser: Expertenstatement im Rahmen des BMZ-Projekts "Virtueller Wasserhandel - Ein realistisches Konzept zum Umgang mit Wasserarmut in Entwicklungsländern?" Bonn, Deutsches Institut für Entwicklungspolitik. Le, Q. B. (2006). A multi-agent simulation of land-use/ cover change: a case study in Vietnam and its adaptation to micro-catchments in Volta River basin (presentation). ZEF's International Advisory Board Meeting, 10. October 2006. Bonn/ Germany. Rogmann, A. (2006). An Introduction to the possibilities of spatial data storing and the possibilities of spatial data storing and access within the GVP. Exemplified on ESRI-Geodatabases". GLOWA-Volta Documentation of research. Schraven, B. (2007). Irrigate or Migrate? Knowledge and Decision Making about Dry Season Economic Strategies in Peasants Households in Northern Ghana. Field report. ZEF/ Bonn. Spalthoff, D. (2006). Water Negotiations, Civil Society and Knowledge: The Case of Urban Water Supply in Ghana. PhD research proposal, GVP/ ZEF. Bonn/ Germany. Spalthoff, D. (2007). Household water use study in two poor areas of Accra: Old Fadama/ Sukura (data report). Bonn/ Germany, ZEF.
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Tsuma, W. (2007). Actors, alliances & power in negotiations. The case of gold mining concessions in Tarkwa Area of Ghana. Field report. GVP/ ZEF, Bonn/ Germany. Wittig R., Hahn-Hadjali K., König K., Schmidt M., Szarzynski J. & Thiombiano A. (2006). Dynamik von Flora und Vegetation in der westafrikanischen Sudanzone am Beispiel von Burkina Faso. Ber. d. Reinh.-Tüxen-Ges. 18, Hannover: 57-68. Youkhana, E. and I. Eguavoen (2006). A comparative analysis of management options for small town water systems after the water sector reform in Ghana. GLOWA-Volta Documentation of research, Bonn. Youkhana, E. and C. Sebaly (2006). Mapping the Water Sector in Burkina Faso. Documentation of research. GVP/ ZEF/ Bonn.
Youkhana E., Wittkötter P. & Zug L. (2008). Institutional Map of Ghana and Burkina
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