1

The impacts of watershed management on land use and land cover

dynamics in Eastern Tigray (Ethiopia)

Fikir Alemayehu1,2*

, Nurhussen Taha1, Jan Nyssen

3, Atkilt Girma

1, Amanuel Zenebe

1,

Mintesinot Behailu1, Jozef Deckers

4, Jean Poesen

4

1Department of Land Resource Management and Environmental Protection, Mekelle

University, P O Box 231, Mekelle, Ethiopia

2Melca Mehaber, P.O.Box 110533,Addis Ababa,Ethiopia

3 Department of Geography, Ghent University, Krijgslaan 281 S8, B-9000 Gent,

Belgium

4Department of Earth and Environmental Sciences, Katholieke Universiteit Leuven,

Celestijnenlaan 200E, B-3001 Leuven, Belgium

Abstract

Integrated watershed management (IWSM) was implemented to address issues of

poverty and land resource degradation in the 14 500 ha upper Agula watershed, in

semiarid Eastern Tigray (Ethiopia), an area known for poverty and resource

degradation caused by natural and man-made calamities. The purpose of this study

was to assess the impact of IWSM and determine the land use and cover dynamics

that it has induced.

The change in land use and cover was assessed by integrating remote sensing and

geographic information systems (GIS). Two sets of aerial photographs (taken in 1965

and 1994 at scale of 1:50,000) and Landsat ETM+ image (taken in 2000 with 30 m

resolution) were used to produce the land use/land cover map and assess land use

change.

The results reveal significant modification and conversion of land use and cover of

the watershed over the last four decades (1965-2005). A significant portion of the

watershed was continuously under intensively cultivated (rainfed) land. The area

under irrigation increased from 7 ha to 222.4 ha post intervention. The area under

dense forest increased from 32.4 ha to 98 ha.

* Corresponding author: fikiral@yahoo.com

Fikir Alemayehu, Nurhussen Taha, Nyssen, J., Atkilt Girma, Amanuel Zenebe, Mintesinot Behailu,

Deckers, J., Poesen, J., 2009. The impacts of watershed management on land use and land cover

dynamics in Eastern Tigray (Ethiopia). Resources, Conservation & Recycling, 53: 192-198.

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The study further shows that IWSM decreased soil erosion, increased soil moisture,

reduced sedimentation and run off, set the scene for a number of positive knock-on

effects such as stabilization of gullies and river banks, rehabilitation of degraded lands.

IWSM also resulted in increased recharge in the subsurface water.

This study reconfirms the importance of IWSM as a key to improve the land use

cover of the watershed towards poverty alleviation and sustainable livelihood.

Key words: Integrated watershed management, land use and cover change, remote

sensing, geographic information system (GIS), soil and water conservation,

catchment management

1 Introduction

Land use describes the way and the purposes for which human beings employ the land

and its resources. Land cover refers to physical characteristics of the land including

human-made structures, which make up the earth’s landscape. Historically, land use

and cover changes have occurred primarily in response to population growth,

technological advances, and economic opportunity (Turner et al., 1995). Human

activities have directly or indirectly modified the natural environment. This is due to

the fact that production demands by humans cannot be fulfilled without modification

or conversion of land cover. Of the challenges facing the earth over the next century,

land use and cover changes are likely to be the most significant (Mustard et al., 2005).

On a global scale, forest, woodland, and grassland have been converted to other uses

during the last three centuries one way or another, to support and satisfy the

increasing demands of the society and economy (Agarwal et al., 2000). Human

intervention caused change in land use such as land clearing, agricultural

intensification, and urbanization, are currently the most consequential components of

global change (Munasinghe and Shearer, 1995).

.

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The consequence of modern society’s demand for more production to meet its

consumption will inevitably result in major modification and conversion of land cover.

Pressures to further convert or manage natural ecosystems for human needs as well as

capturing more of the global net primary productivity are also likely to increase

(Mustard et al., 2005).

Understanding the implication of past, present and future patterns of human land use

for biodiversity and ecosystem function is increasingly important in landscape

ecology (Turner et al., 2003). Historical land use and cover patterns are a means to

evaluate the complex causes and responses in order to better project future trends of

human activities and land use/land cover change. If land use/land cover changes are

not carried out scientifically, the negative impacts on both the environment and the

socio-economic settings are not easily measurable (Gete, 2000). The study of land

use/land cover to yield valuable information for analysis of the environmental impacts

of human activities, climate change, and other forces (Belay, 2002). This has been

particularly important, as changes in land use become more rapidly affecting the

livelihoods of societies. Thus, understanding land use and land cover dynamics of an

area plays a significant role to take corrective measures on land and its use for

sustainable productivity.

This paper presents the land use and land cover dynamics observed after the

implementation of integrated watershed management in Northern Ethiopia. Watershed

management practices are changes in land use, and vegetation cover, with the main

objective of rehabilitation of degraded lands, protection of soil and water systems.

The aim of integrated watershed management is to improve the standard of living of

the population living within the watersheds: decrease population pressure and increase

land productivity so that sustainable livelihoods and land use practices can be secured

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for the population (McCormick et al. 2003). Integrated watershed management

(IWSM) is a multi-objective and multi-disciplinary approach to solving natural

resource management and food security problems in rural communities, particularly

in dry and semi-arid areas where rainfall is scarce (Igbokwe and Adede, 2001). The

overall aim of integrated watershed management is, therefore, to ensure sustainable

natural resource use and equitable growth of communities.

The replicability of land resource management can be justified, if the intervention

approach and the impacts are well assessed and studied. Thus, the research addresses

the impacts of integrated watershed management and the changes that have followed

on land use and land cover dynamics. The aims of this paper are therefore (a) to

assess the land use and cover change that occurred between 1965 and 1994, and

between 1994 and 2005; and (b) to assess the effects of the watershed management on

curbing land degradation and improving agricultural production.

2 Materials and methods

2.1 Site description

The upper Agula watershed where the study was carried out lies between 13°45' to

13°55' N and 39°42' to39°48' E in Eastern Tigray (Fig. 1). The total area of the study

site is 14 500 ha. The area falls in the semi-arid agro-climatic zone having highly

dissected and rugged terrain. The altitude of the study area ranges from 2040 to 2840

m a.s.l. Agro-ecologically it is classified as highland and midland areas with mean

annual air temperature of 22.8 o

C and maximum 27.2oC and an annual precipitation

ranging from 515 mm to 872 mm (Gebremedhin, 2004). The area has a bimodal

rainfall pattern. The small rains occur between November and March and the major

rainy season from June to September. The small rains are not reliable and insufficient

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for crop production. Soils are predominantly light coloured, sandy mainly of

metamorphic origin (Gebremedhin, 2004). Subsistence agriculture is the major stay

of livelihood of the people. The major crops of the study area are barley (Hordeum

vulgare), wheat (Triticum sativum), teff (Eragrostis teff) and millet (Eleusine

coracana).

The erratic rainfall coupled with poor soils and a low ground cover and a high human

and livestock population pressure on land resources have contributed to a multitude of

serious problems, such as degradation of vegetation cover, accelerated soil erosion,

crop yield decline and human suffering. To address these serious and urgent problems

Integrated Watershed Management measures are underway in Upper Agula watershed

since 1998. The project has been implemented by Eastern Tigray Development

Programme with the support of Irish Aid. It was a three years resource management

and development project. The purpose of this intervention was to adopt integrated

watershed management as a technological intervention averting the land degradation

and restoring a farming system with a scope for modern agriculture (Fig. 2). The

components of the intervention include: physical and biological soil and water

conservation, (including gully stabilization, hill side terracing, exclosures and planting

on hill slopes (forage grass and (multi-use) trees) , irrigation, horticulture, beekeeping,

and improved crop technology. The budget for the implementation of various

activities was 166,666 € (Igbokwe and Adede, 2001).

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2.2 Data source and analysis of time series images

The research focuses mainly on detecting changes, delineatin, and mapping areas that

have experienced land use/land cover change over a forty year time period (1965-

2005) using aerial photographs and Landsat imagery.

The data for land use/cover were obtained from aerial photographs of 1965 and 1994,

with an approximate scale of 1:50,000. In order to detect the change after intervention,

a satellite image (Landsat with 30 m resolution taken on February 2000) was analysed.

Contour lines were digitized from 1:50,000 topographic maps with 20 m contour

interval. The digitized contours were interpolated to produce a Digital Elevation

Model (DEM) in ILWIS GIS software. DEM was used to transform the aerial photos

to orthophoto for the delineated area.

Aerial photographs, satellite images, and topographic maps were geo-referenced using

50 ground control points collected from GPS readings. From the geo-referenced aerial

photographs an orthophoto mosaic was created. Processing of images was carried out

using ILWIS GIS software and Arc view (version 3.2) software.

Preliminary aerial photo interpretation and classification of each land use/land cover

type was delineated from aerial photos (1965 and 1994) using mirror stereoscope.

Normalized Difference Vegetation Index NDVI was produced from TM band 4 and

TM band 3 that is (TMB4-TMB3)/ (TMB4+TMB3) to enhance the land cover of the

study area. The land use/land cover classes from the Landsat image were produced

from visual interpretation and digitized on screen using ILWIS GIS software.

The description given for land use land cover classification was adapted from the

Land use and land cover of Tigray region prepared by BoANRD (2001) (Table 1).

However intensive field survey was carried out to check the preliminary interpretation

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and necessary corrections were taken. The field assessments were conducted with

help of mobile pocket computer (IPAQ GPS mounted) which holds the geometrically

corrected aerial photographs and satellite image interpretation maps. The field survey

helped to update the (2000) Landsat image in order to generate the current land use

and cover map for 2005.

In addition to data collected from image processing, focused group discussions were

organised to obtain information around specific topics allowing different groups of

people to express their opinion and views and reflect on key issues such as natural

resources management, land use and land cover dynamics and environmental change.

Moreover a total number of 90 households were selected for this study. After

acquiring the list of households, a systematic random sampling procedure used to

select a total of 90 sample households. For the purpose of this study both structured

and semi-structured (with open and close end questions) questionnaires were prepared

to conduct the research. The survey had a set of questions related to demographic

characteristics, crop and livestock proportion, household assets on (land holding,

livestock, beehives e.t.c.), land use and management, were the main issues included

(both before and after intervention with a marked year).

3 Results

3.1 Land use and land cover change detection over the period 1965-2005

Eighteen major land use and cover types were identified. (Table 2 and Fig. 3). During

the period 1965-2005 intensively cultivated land constituted more than 50 % of the

catchment (Table 2 and Fig. 4). Detection of land use and cover for a period of four

decades showed a change on dense forest, bush shrub land, shrub land, built up area

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and wetland (Fig. 4). The area under assured well irrigation increased from 7.1 ha to

222.4 ha after the intervention. Correspondingly, the area under dense forest increased

from 32.5 ha to 98 ha (Fig. 5).

In 1994 important changes in land use and cover were observed: wooded shrub

grassland, shrub grassland, bare land and wet land ceased to exist. On the other hand

new land cover types emerged in 1994. These include dense woodland (5.6 ha),

open/bushed woodland (10.9 ha) and wooded grassland (192.4 ha). (Table 2).

However, in 2005 the land cover types wetland and bare land re-emerged (Table 2

and Fig 3. and Fig. 4).

3.2. Observed changes on vegetation, soil, groundwater and farm produce

following the watershed management

The conservation efforts implemented in 1998 were to reduce soil erosion and to

maintain or improve the productive capacity of soil resources. Thus, following the

IWSM interventions, observations focussed on reduction of soil loss, vegetation cover,

soil moisture increase and land productivity. The combination of different soil and

water conservation measures had the potential to reduce surface run-off and erosion,

this in turn increase infiltration. Before the intervention, most of the study area used to

be affected by recurrent flooding hazard coming from the upper slopes and sediment

deposition took place; 50% of the respondents living in the middle of the catchment

were affected. After the implementation the problem of flood hazard and

sedimentation in the middle watershed was completely solved.

Since 2003, 115 wells have been developed in the study area. Most of the wells are

found on the middle catchment, where the ground water gives a good response to

increased infiltration on the upper slopes. Here, water is available within 1-2 m, while

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in the lower catchment water depth is between 8-10 m. The availability of wells has

opened up an opportunity for 97 households to grow crop and vegetables twice a year.

On the eastern slopes of the catchment, honey production is important. This is related

to the increased availability of water (development of new water resources), and

improvements in the ecology of the adjacent area through exclosure measures. Before

intervention traditional hives were used by respondents, and the honey obtained was

in the range 4-5 kg/harvest. After the intervention, respondents indicated that honey

obtained from modern beehives has increased tremendously and has now reached 20-

25kg/harvest and farmers are able to harvest twice a year.

Before the intervention very few households had knowledge on how to make different

kinds of physical structures of SWC to prevent soil erosion. After the intervention,

most households in the survey (89%) have adopted and practice stone-faced trench

bunds and hillside terracing. These conservation measures are easily replicable and

cheap and the practice is spreading to other areas at a fast rate. 50% of farmers are

preparing compost in the house or on their plots so as to keep the fertility of the soil.

75% of households are planting trees on their own plots or around the homestead with

the purpose of protecting farm fertility and supplementing incomes. 45.6% of

households now have access to irrigable land, 60% of them have improved their

houses into tin-roofed structures and 60% of respondents now have food available

from 5-8 months.

Adoption of conservation agronomic practices in the watershed resulted in better

productive performance of crops over time due to decrease in soil erosion and

enrichment of the soil. The three most important crops (teff wheat and barley) have

all shown marked yield increases between 1997 and 2004. Specifically, average teff

yields have increased from 0.3 t/ha to 0.6 t/ha, wheat has increased from 0.5 t/ha to

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0.8 t/ha and barley has increased from 0.45 t/ha to 0.75 t/ha. Combined with increased

fertilizer use, the adoption of conservation agronomic practices in the watershed

resulted in better productive performance of crops due to decreases in soil erosion, in

flooding and to enrichment of the soil.

4. Discussion and conclusions

4.1. Causes of land use and land cover changes between 1965 and 1994

Remote sensing and GIS based change detection studies have predominantly focused

on providing the knowledge of how much, where, what type of land use and land

cover change has occurred (Weng, 2002). The aerial photo interpretation reveals that

there was an expansion of cropland between 1965 and 1994. During this period

sparsely cultivated land, wooded shrub grass land and shrub grass land have vanished.

This is due to population pressure which results in the expansion of agricultural land

and settlement. The predominant motive for land use change is production of food and

fibre (Mustard et al., 2005). As stated by the farmers, the catchment was covered

mainly by natural vegetation until the 1960s, with dominance of Juniperus and Acacia.

Still the remnants of these trees are found around churches and communal areas in

small patches. Furthermore, growing pressure from human and livestock population

and the repeated drought conditions caused forest devastation for fuel wood trade as a

means of income to overcome the drought period.

The 1965 aerial photographs show the presence of wetland in plain areas following

valley bottoms and along rivers in the catchment. Farmers confirmed that they used

the wetland for grazing purposes. However, this land cover feature had disappeared in

1994 due to mainly removal of vegetation cover. Change in vegetation cover can alter

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surface fluxes of energy and water and modify surface climate (Mustard et al., 2005).

Consequently, human induced soil degradation was exacerbated.

4.2. Causes of land use and land cover change between 1994 and 2005

The rehabilitation of vegetation in many places of the catchment has improved the

forest cover. Farmers also confirmed during focus group discussions, that the

vegetation cover has increased and the change that has been observed at present was

the result of the intervention i.e. the establishment of exclosures. Riparian trees along

the valley bottoms following the rivers which had not been observed in 1994 have

developed in 2005. This was well observed during the field surveys. The trees were

planted during the forestation activities to stabilize gullies.

Though their numbers are small, remnants of natural forests are found around

churches and on steep slopes. The degraded shrub grassland which covered a large

portion of the watershed in 1994 was generally converted into other cover types such

as shrub-grassland. This was observed during field surveys in which the vegetation

cover that was very small and scattered in 1994 has at present grown up and changed

into shrub-land, bush shrub grassland and bush-grassland. In some areas trees 3 m tall

and above were observed. Hence the improvement of the vegetation cover has

certainly been the result of the extensive soil and water conservation work that had

been implemented in the study area. The 1994 aerial photograph analysis results show

that intensively cultivated land constituted a larger portion of the catchment (55.11%),

when compared with 1965 (51.1%) and 2005 (51.7%). The above changes explain the

reduced bush and shrub cover in 1994.

On the other hand, a remarkable increment was observed in built up areas compared

with 1994. This change was the result of the expansion of the two towns Atsbi and

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Haike Meshal. The two towns were still small on 1994 and recently both towns are

expanding at the expense of cultivable and grazing land.

The wetland that had disappeared in 1994 re-emerged in 2005 (Fig. 6.). The wetland

has indeed developed as a consequence of extensive gully treatment to prevent

flooding and erosion. A review by Nyssen et al. (2004) indicates the benefits of soil

and water conservation (SWC) measures in controlling runoff and soil erosion.

Wetland development of the flat plain area in the lower and middle catchment is

attributed to SWC structures such as check dams in gullies and trenches dug to

intercept and store runoff. Farmers stated this cover type is a recent phenomenon

following the stabilization of gullies. The emergence of wetland is attributed to the

improvement of vegetation cover and the intensive soil conservation measures

undertaken in the upper watershed. This change is taken as an indicator of the success

of the SWC measures, because following the emergence of wetland there has been an

increase of the groundwater table which is tapped through shallow wells.

4.3. The impacts of IWSM on land use and cover change

The erratic rainfall coupled with poor soil and ground cover and high human and

livestock population pressure on land resources have contributed to a number of

serious problems, such as degradation of vegetation cover, accelerated soil erosion,

crop yield decline and human suffering.

The major observed changes during the last four decades were the conversion of

forest land, bush, shrub, and woodland to cropland, grazing land, and built-up areas.

A similar land use and cover study made by Solomon (1994) in southern Ethiopia

indicated that the influence of land use and cover depends very much on the nature of

the land and the level of management techniques used. The rapid changes in land use

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and cover of the study area has been driven by factors such as population pressure,

expansion of rural towns, large-scale overgrazing, and recurrent drought and poor

land management. Marked land use/land cover dynamics are also observed in dense

forest, wetland, shrub-land, and intensively cultivated (irrigation) land.

The positive impact of the watershed management in the study area could be

explained in terms of reduced soil erosion rates, increased soil moisture availability

which could be deduced from the increased in crop production, reduced sedimentation

and flooding problems in the lower parts of the watershed, stabilized gullies and river

banks, rehabilitation of degraded lands and improved ecological balance in general.

Similar studies elsewhere in northern Ethiopia (Woldeamlak, 2003; Liu et al., 2008;

Munro et al., 2008; Nyssen et al., 2008) reported the effectiveness of sustained

conservation efforts at catchment level in controlling soil erosion and in improving

hydrology and land productivity. The improvement of vegetation cover in the

watershed decreased the depth to the groundwater which could be managed and used

for irrigation.

4.4. Conclusion

The studied watershed underwent remarkable changes in land use and covers during

four decades and the changes exhibit a dynamic nature. Throughout the period 1965-

2005 more than half of the watershed was occupied by intensively cultivated land.

Over the forty years observation period, the area under assured well irrigation

increased from 7.1 ha to 222.4 ha (see also Fig. 7). The area under dense forest

increased from 32.5 ha to 98 ha.

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Major observed changes after the implementation of integrated watershed

management are: reduced soil erosion, and increased soil moisture availability which

could be explained by the increase in crop production, increased ground water

recharge (as observed in the abundance of shallow wells), reduced sedimentation and

run off problems in the lower parts of the watershed, stabilized gullies and river banks,

rehabilitation of degraded lands and improved ecological balance, introduction of

modern beehives and increase in honey production.

To conclude, ecological changes caused by the destruction of natural vegetation,

removal of soil by erosion and drying out of rivers as the result of mismanagement of

land have been reversed as a result of the integrated watershed management

intervention. While the IWSM intervention researched shows encouraging results for

both vegetation cover and farmer livelihoods, in order to be sustainable, it is essential

to maintain a high level of farmers participation. The study highly recommends the

up-scaling of such intervention in similar agro-ecologies.

Acknowledgements

The authors wish to thank Habtamu Mulatu, Fekadu Getnet, Ermiyas Ayenekulu and

Steven Fisher for their useful comments and suggestions that helped to improve this

paper. Funding for this study was provided by the VLIR - Mekelle University IUC

Programme. Farmers and authorities from Hayke Meshal and surrounding villages are

greatly acknowledged for their hospitality.

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Table 1. Description of land use and cover classes used for analysis of change

between 1965, 1994 and 2005

Land cover type Description

Intensively cultivated

land

Annual and perennial crops (> 70 % of the land), frequently observed on

level lands (plains, plateaus, foot slopes and valley floors).

Moderately cultivated

land

Annual and perennial crops, covering 40-70 % of the land; includes large

patches of woods, shrubs, and grasses.

Sparsely cultivated 20-40%. of the mapping unit is under cultivation; the rest is constituted of

shrubs, grassland, degraded land, exposed rocks and sands.

Dense forest Remnant of high natural forest, found in small patches around churches,

steep slopes and less populated areas. Canopy cover of 50-80%.

Dense woodland Total canopy cover around 90%, typically a mix of trees (60 %), shrubs

(20 %), grasses (10 %) and unproductive or unutilizable land (10 %).

Open/bushed woodland Canopy cover of 65%, with 30-40 % trees, 15-25 % bushes, 20% herbs and

grasses and 15% unproductive bare land.

Wooded shrub grassland Composed of trees, high shrubs, and low herbs.

Wooded grass land Consists of trees and herbs; an intermediate between grassland and

woodland.

Wooded bush grassland Composed of trees, bushes and grasses

Bush shrubland Constituted by strata of very few trees, bushes, shrubs and scattered herbs

or grasses. The canopy cover of bush/shrubs is 40-60% and that of herbs or

grasses is 15-20%

Bush shrub grassland Consists of a stratum of bushes, shrubs and herbs/grasses.

Shrubland Consists of shrubs, usually not exceeding 3m in height, with a canopy

cover > 30%. Ground cover often poor and composed of patches of dense

and open shrublands, grasslands and some scattered trees.

Shrub grassland Consists of grassland with scattered or grouped shrubs.

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Open grassland or shrub

grassland

Consists of open grassland, shrubs and very few trees; found scattered all

over the region in flat water logged ares and on steeper slopes.

Degraded shrub

grassland

Characterized by strata of shrubs and grasses or herbs.

Bare land

Land devoid of vascular plants; composed of exposed rock, sand and soil

surfaces.

Built-up area Residences, administrative buildings, small industrial and trade enterprises.

Wetland Water table at or near the surface, grasses and widely scattered or grouped

trees around the riverbanks.

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Table 2. Land use and cover changes for the period 1965-2005 in upper Agula

watershed

1965 1994 2005

Cover type Area

(ha)

% Area (ha) % Area

(ha)

%

Intensively cultivated

land(rainfed)

7405.1 51.1 7980.2 55.1 7483.5 51.7

Intensively cultivated (irrigation) 7.1 0.1 55.2 0.4 222.6 1.5

Moderately cultivated land 525.7 3.7 68.2 0.5 330.1 2.3

Sparsely cultivated land 1889.6 13.3 - - 557.7 3.9

Dense forest 37.5 0.3 32.5 0.2 98.0 0.7

Dense woodland - - 5.6 0.1 - -

Open/Bushed woodland - - 10.9 0.1 352.6 2.4

Wooded shrub grassland 113.6 0.8 - - 47.8 0.3

Wooded grassland - - 192.4 1.4 538.0 3.7

Bush shrub-land 1475.3 10.4 177.0 1.2 358.8 2.4

Bush shrub grassland 325.7 2.3 1392.6 9.7 1241.7 8.6

Shrub-land 415.9 2.9 114.7 0.8 1248.7 8.6

Shrub grassland 1268.0 8.9 - - 179.8 1.2

Open grassland/shrub grassland 293.4 2.1 80.0 0.7 25.7 0.2

Degraded shrub grassland 251.8 1.8 4295.2 30.0 1224.9 8.5

Bare land 235.9 1.7 - - 331.0 2.3

Built up area 35.0 0.3 73.1 0.5 244.1 1.7

Wetland 198.4 1.4 - - 215.7 1.5

Total 14,477.9 100 14,477.9 100 14,477.9 100

20

Fig. 1. Location map of the study area

Fig. 2. Physical soil and water conservation structures such as stone bunds, soil bunds

and runoff collection ponds are also part of the improved land management in the

watershed.

21

1965 1994 2005

Fig. 3. Land use and cover changes in the upper Agula watershed 1965-2005. The archipelago-like land units that appear at the south-west of the

catchment, correspond to irrigated land, located downstream of the catchment and which is gradually expanding.

22

IC (rainfed) IC(irrgated) Dense forest Bush SL Shrub land Built-up Wet land

0

2

4

6

8

10T

ho

usa

nd

s (h

a)

1965 1994 2005

7405

7980

7483

222

1475

192358 415

114

1248

244 198 2157 37 32 98 35 7355

Fig. 4. Major land use and cover changes from 1965-2005 (IC = intensively

cultivated; SL = shrub-land)

Fig. 5. Olive (Olea europaea ssp. africana) forest in the upper part of the catchment

23

Fig. 6. Expansion of wetlands in the valley bottoms

Fig. 7. Ground-based photo-monitoring of the area downstream of the watershed. The

upper photograph was taken in 1975 (© Neil Munro), the lower in 2006 (© Jan

Nyssen). An irrigation scheme was developed in this valley floor, some 10 km

downstream from the watershed (extreme SW of the 2005 map– see Fig. 3). Despite

the fact that the area is located outside of the formal Watershed Management Project

area, stone bunds and improved vegetation cover on the slopes can be observed. The

fig tree is a permanent element, a control, in this landscape.