deborah ofori research scientist, surface water division

Adaptive management of groundwater resources for small scale irrigation in

sub-Saharan Africa (AMGRAF)

Deborah OforiResearch Scientist, Surface Water Division

Mid-Year Review SeminarWRI Conference Room, 15.07.2014

Outline

Project Information

Background/Introduction of AMGRAF

Baseline Study

Methodology

Progress of Study

Way Forward

Project Information

Unlocking the Potential for Groundwater for the Poor (UPGro)

Aims: To enable developing countries in SSA to use

groundwater in a sustainable way to benefit the poor

Project Information cont.Research Issues

Where GW, how and at what rate is it recharged, and how can it

be more effectively and efficiently abstracted to meet local

needs?

What is the state of the resource – quantity & quality; how will it

respond to abstraction, impact of growing population, climate

change, etc.?

What governance arrangements are needed to support this

access in an inclusive and sustainable way, and in particular to

reach the poorest and most marginalised groups?

Project Information cont.

Funding Natural Environment Research Council (NERC),

Economic & Social Research Council (ESRC) & Department for International Development (DFID)-UK

7-year international research programme - First Phase: Catalyst grant - Second Phase: Implementation of Main Project

Project Information cont.

AMGRAF - Catalyst grant (12 months)

WRI (Ghana) & CSIR (South Africa) – Baseline Studies & Consortium building

Ethiopia – Pilot study

Implementing PartnersCSIR- Water Research Institute, International Water Management Institute (Ethiopia), Geological Survey, Ethiopia, CSIR (South Africa)

Project Information cont.

Aim: To enable sustainable development of accessible

(shallow) groundwater for small-scale irrigation in sub-

Saharan Africa

Concept: is that ‘accessibility’ is more important than

aquifer potential

Working definition: Depth to groundwater should be

less than 25 meters

AMGRAF Baseline Study Title Assessment of Shallow Groundwater Irrigation in the

Upper East Region of Ghana

Project TeamDr Emmanuel Obuobie (RS)Deborah Ofori (RS)Dr Emmanuel Obeng-Bekoe (RS)

Project Duration 1 Year (2013 –2014)

Introduction Study area: Upper East Region (UER) Land area: 8,842 km2 (4% of Ghana) Slope: < 2% Region is largely drained by the

White and Red Volta rivers

Introduction cont.

UER is located in the Sudan-savannah climate zone and can be described as semi-arid

Rainfall pattern is mono-modal with distinct wet (May-Sept/Oct) and dry (Nov-April)seasons

Rainfall is characterized by high temporal and spatial variability

Dry spells during rainy season Mounting evidence of Climate

variability and change GW offers a more food secure

alternative to rain-fed farming

Climate - UER

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

50

100

150

200

250

25

27

29

31

33

Precipitation Evapotranspiration Temperature

Month of YearPr

ecip

itatio

n/PE

T (m

m)

Tem

pera

ture

(oC)

Long-term mean rainfall, PET and temperature at Bolgatanga (UER)

Introduction cont.

Population in 2010 (GSS, 2012): 1,047,545 – 48 % males & 52% females

High population density (118 persons/km2) Settlement is largely rural (84% rural, 16% urban) &

large farming households (~ 6) Predominant occupation is small scale farming (84 %

of households)- GSS 2012 >80 % of population live below official poverty line

(GHC 90 or US $34) – GSS 2012 About 80% of population depend on GW for water

supply; GW for irrigation is limited

Demography & Socio-economic

Introduction cont.

Objectives Understand the characteristics of shallow

groundwater irrigation (SGI) Assessment of groundwater (shallow)

resources & characteristics Understand groundwater governance

structures and linkages at levels of management

Investigate socio-economic drivers for SGI

Methodology

Review of WRI work on groundwater Review of studies on shallow irrigation (IWMI

work & other studies) & groundwater assessment

Stakeholder consultation (Institutions, farmers, MOFA, etc.)

Progress of Study

Shallow groundwater Irrigation (SGI)

Resource Assessment

Shallow groundwater Irrigation

Major uses of groundwater in the UER SGI is categorized as informal irrigation, mainly

during dry season low-lying areas such as flood plains, alluvial

channels and valley bottoms where the water table is high

Manually tapped using simple tools & indigenous knowledge

Hand-dug wells usually less than 10 m deep

Shallow groundwater Irrigation cont.

Water is lifted & distributed using : rope and bucket/ container, &motorized pumps

Many farmers have 2 or more wells Farm sizes ranges between 0.01-0.5 ha Major Crops: tomatoes, onions, pepper, leafy

vegetables Farmers usually do not own the land; have

some arrangements with landowners that allow them to cultivate

Progress of Study cont.Resource Assessment 2 main geological formations: Precambrian crystalline

rocks & Paleozoic sedimentary consolidated rocks

L E G E N D

International BoundaryRegional BoundaryGeological Boundary

FORMATIONS

Buem VolcanicsBuem

Togo Series

Tarkwaian

Upper BirrimianLower Birrimian

Basic Intrusives

Granite

Obosum Supergroup

Damongo MassifGambaga Massif

11°

8°

9°

3°

10°

2° 1°

N

0° 1°

0 50 Km

Regional Capital

Tossiegou

Oti Beds

{

{ }

}

Resource Assessment cont.

3 main Aquifer zones: weathered zone, bedrock-weathered zone interface, fractured zone

Aquifer zones & types

Schematic representation of the hydrogeological profile in the Precambrian crystalline rock in the Upper East region (Obuobie et al., 2013)

Resource Assessment cont.

Borehole characteristics

Summary of borehole information in the Upper East Region (Agyekum et al., 2008)

District map of the Upper East Region (2008 map)

Based on data from 2,458 successful boreholes

Resource Assessment cont.Groundwater Recharge

Groundwater recharge for specific locations in Ghana (Obuobie and Barry, 2012)

Recharge is mainly through precipitation (direct & indirect) Contribution from regional aquifers is insignificant

Resource Assessment cont.Simulations by Models Obuobie & Ofori (2013):Huge potential for groundwater use in the Basin including the UER

Map of groundwater potential zones of Ghana (source: Gumma and Pavelic, 2012)

Groundwater development potential map of northern Ghana (source: Forkuor et al., 2013)

Resource Assessment cont.Groundwater quality Based on analysis of water samples from 214 boreholes

Summary of groundwater quality in the Upper East Region ( Amuzu, 1974 cited in Agyekum et al., 2008)

Socio-economic & Governance

Stakeholder consultation is underway

Way Forward

Complete the stakeholder consultation process

Understand the socio-economic drivers for shallow ground irrigation

Identify key issues, challenges & opportunities for GW resources & SGI

Identify knowledge and data gaps in groundwater resource assessment, etc.

Identify knowledge gap in groundwater governance

Thank You