Cornell's Master of Professional Study Program in Integrated Watershed Management and Hydrology
at Bahir Dar University, Ethiopia
Determination of household participation in water source management: Achefer,
Amhara region, Ethiopia.
Access to safe drinking water supplies and sanitation services in Ethiopia are among the lowest
in Sub-Saharan Africa. While governmental and nongovernmental organizations have been implementing water supply and
sanitation projects in recent years, many fail shortly after construction due improper management. In this study
we examine socio-economic, institutional and exogenous factors which affect households’ participation in the
management of water sources. A survey was carried out involving 16 water supply systems and 160 households within
Achefer area, in Amhara, Ethiopia. In addition, the water quality of eight water points was tested. The results
show that households’ demand for sustainable water services are positively affected by users’ participation
during the project design and implementation, advocacy provided by the project and greater household income.
Thus, for drinking water systems to be sustainable these factors should be included in planning water supply
projects. Full thesis.
Assefa Derebe Zegeye:
Assessment of upland erosion processes and farmer's perception of land
conservation in Debre-Mewi watershed, near Lake Tana, Ethiopia.
Soil erosion is affecting global food security. Though it is a natural process, its
rate has increased significantly during the last century mainly by human activity. Indeveloping countries
in order to combat erosion, many soil and water conservation practices have been proposed but only a few,
if any, are implemented by farmers on a long-term basis. Therefore, this study sets out to evaluate upland
erosion and evaluate the effectiveness of practices used by farmers and the farmers’ perception about
erosion and control practices and to identify factors affecting farmers’ land conservation decision-making
processes. The watershed chosen was Debre-Mewi located south of Bahir Dar, 30 km from Lake Tana. In this study,
the paper presents and discusses the results of the 15 surveyed agricultural fields and personal interview of
80 households conducted in the Debre Mewi watershed. To quantify the amount of soil loss due to rill erosion
in the watershed, each rill’s dimensions were carefully measured to determine its volume and hence to obtain
average magnitudes and rates of soil erosion for the fields. The result showed that the average soil loss
in the surveyed fields was 36t/ha provided that the contribution of inter-rill erosion assumed to be 25% of
the actual soil loss (taken from different literatures). Sediment measured from the control plot of AARC
experimental station located within surveyed fields was estimated as 38.3 t/ha whereas using USLE model
predicted 39 t/ha. Thus, all three methods gave similar results. The knowledge and perceptions of the
farmers about erosion problems and mitigation measures, their reasons for not carrying out periodic
maintenance and construction of new conservation measures and conservations practices that are widely
used by the farmers are also discussed in this paper.
Tenagne Addisu Wondie:
The impact of urban storm water runoff and domestic waste effluent on
water quality of Lake Tana and local groundwater near the city of Bahir Dar, Ethiopia.
In urban areas, the main task of town planners and engineers is providing drainage
structures to prevent flooding. Recently the effect of these drainage structures on water
quality has become a concern. However, little is known about the magnitude of the
pollution. There fore the objective of this study is to characterize pollution loads from
one Ethiopian urban area, Bahir Dar, on the southern end of Lake Tana which is
experiencing dramatic expansion. In particular this research measured the quantity and
quality of storm runoff and ground water. To determine the pollutant concentration
and its effect on the quality of ground water, three shallow wells were installed. Urban
storm water runoffs at six storm drains, which empty to Lake Tana, were instrumented
for discharge and water quality measurements. The quality parameters considered
were the total coliform, dissolved oxygen, total solids (TS), total suspended solids
(TSS), biological and chemical oxygen demand (BOD/COD), total nitrogen (TN),
total phosphorus (TP), pH, and conductivity. Three-rainfall event samples were taken
in each month during rainy season (July, August, September and October) for a total
of 9 rainfall events. Magnitude of pollutant load concentration flowing in to Lake
Tana during low and high storm flow and contributions to groundwater were
determined. In addition low flow characteristics (base flow) was determined once in a
month. The results indicate that the water quality parameters like total nitrogen; total
phosphorus and total suspended solids are found to be high with an average
concentration load of 22.8mg/l, 0.46mg/l and 365mg/l respectively. The average
concentration for dissolved solid, electric conductivity, dissolved oxygen COD, and
total coliform are178mg/l, 338ì/cm, 2.8mg/l, and 3.28mg/l and169coli/100ml
respectively. From the six sub watersheds assessed in this study, the sub watershed
that drains the hotel discharge (station-5) had the elevated concentration for all
pollutant except dissolved oxygen. All runoff concentration means found in this study
area except the mean recorded for chemical oxygen demand, are higher than the
means found in the data base for North American cities (CDM and NURP) and it
shows that the Bahir Dar storm water runoff pollutant load is in excess of the North
American cities. Full thesis.
Zelalem Kassahun Tesemma:
Long term hydrologic trends in the Nile bsain.
A study has been conducted to examine if and how streamflow in the Nile Basin has
varied over the period of available records. Streamflow records from 13 flow gauging
stations in four major river basins of the Nile and 38 precipitation stations all over the
Nile basin were studied. Monthly measured discharge (1912-1982) and rainfall data
for those selected stations were collected from four different data sources and Global
Hydro Climate Data Network available at http://dss.ucar.edu/datasets/ds553.2/data/
and Global Historical Climatology Network available at http://gpcc.dwd.de were
selected as the main data sources except those Ethiopian stations. The remaining
recent 20 years data were collected from countries. Monthly and annual streamflows
(up to the year 2000, some up to 2007) were extracted and analyzed for each of the 13
station. The raw data were validated thoroughly by comparing different sources,
corrected and augmented if needed.
The Mann-Kendal and Sen’s T non-parametric test was used to detect significant
trends in the selected years in combination with the Trend Free Pre-Whitening
(TFPW) method for correcting time series data from serial correlation. The slope of
the data set was computed using the Thiel-Sen Approach (TSA). For this study a 5-
percent level of significance was selected to indicate the presence of statistical
significant trends. Rainfall-Runoff Modeling was done on the upper Blue Nile using
the Thronthwait-Mather model to understand the land cover changes on runoff over
the past 30 years.
The mean annual natural streamflow on the Blue Nile Stations (Bahir Dar, Kessie and
El Diem) show no trend. The rainfall over the basin also shows no significant trend.
The Monthly runoff showed moderate variability at El Diem with 19% and 34% at
Bahir Dar and Kessie. This might be a result that more land was cultivated growing of
different crops as shown by rainfall-runoff modeling over the last 30 years. White Nile
Stations (Jinja, Mongalla and Malakal) show a significant increasing trend on both
rainfall and streamflow. The runoff increased 72%, 67% and 20% of the mean annual
flow at Jinja Mongalla and Malakal respectively. Stations of the Main Nile
(Tamaniate, Hassanab and Dongolla) show significant decreasing trend in streamflow
due to abstraction of flow before reach gauging stations. For water resources
management the key conclusion, that Nile natural streamflows have not changed
significantly during the last 100 years. Full thesis.
Tigist Yazie Tebebu:
Assessment of hydrological controls on gully formation near Lake Tana,
northern Higlands of Ethiopia.
Over the past five decades, gullying has been widespread and has
become more severe in the Ethiopian highlands. Besides negatively affecting
soil resources, lowering crop yields in areas between the gullies and reducing
grazing land available for livestock, gully erosion is one of the major causes of
silting of reservoirs. Assessing the rate of gully development and the
controlling factors of gullying will help to explain the causes for current land
degradation and to design reliable conservation measures for already existed
gullies and preventing strategies for those areas susceptible to further gullying.
The study was conducted in the 523 ha of Debre-Mewi watershed south of
Bahir Dar, Amhara region, Ethiopia. A comparison of the gully area estimated
from 0.58 m resolution quick bird image with current gully area walked with a
garmin GPS, indicated that the total eroded area of gully was increased by
43% and 60% from 0.65 ha in 2005 to 1.0 ha on 2007 and 1.43 ha on 2008.
Semi structured group interview and monitoring of gully development through
time was made with profile measurements of contemporary gully volumes.
Gullying started in the beginning of the 1980`s followed the clearance of
indigenous vegetation, leading to an increase of surface and subsurface runoff
from the hillside to the valley bottoms. Gully heads retreat into the hillslope
during the rainy season. The water levels of gully contributing area showed
that actively eroding sections the water table was in general closer to the
ground surface on the gully shoulder than in stabilized sections. Piping and
tunneling together with a high water table facilitate the slumping of the gully
wall and their retreat. Estimated long-term average soil loss rate by gully
erosion in the mid slope gully was 21 t ha-1 yr-1 and 27 t
ha-1 yr-1 in the valley
bottom saturated gullies. The area specific short-term gully erosion rates
between 2007 and 2008 were approximately 128 t ha-1 yr-1 for the midslope
gully and contributes to 1.7 cm soil loss for the 16.5 ha watershed and 402 t
ha-1 yr-1 for the valley bottom gully (equivalent to 3 cm soil loss of the 17.4 ha
watershed) Full thesis.
Tilashwork Chanie Alemie:
The effect of Eucalyptus on crop productivity, and soil properties in the
Koga watershed, western Amhara region, Ethiopia.
This study was conducted at the Koga Watershed in the Western Amhara
region of Ethiopia. The main objective of the study was to observe if the Eucalyptus
plantation is harmful for the ecosystem. The study through key informants’ interview
proved that almost all local farmers perceive that Eucalyptus trees are exhausting the
once productive land because of its fast growth. Water points dried up, too. Despite
this, the growers insist on planting Eucalyptus because of its fast biomass production
to sell it after relative short time for cash income and use in construction. A triplicate
experiment was established to understand the effect of Eucalyptus on soil properties,
crop production and water bodies. Its effect was compared to other land uses such as
Croton macrostachyus border plantation along maize farm (regarding soil bulk
density, moisture content and maize plant count and height) and coffee garden
(concerning undergrowth density). There were no pronounced changes in soil bulk
density, organic matter, texture, pH, exchangeable potassium and available water
capacity due to Eucalyptus hedgerows along maize farmland. Eucalyptus trees
significantly affect available phosphorus (avail. P), exchangeable calcium (exch. Ca),
total nitrogen (TN), moisture content (MC), soil hydrophobicity, light intensity and the
density of the undergrowth. At 5 m distance from Eucalyptus stand, there were the
greatest reductions of values of avail. P (3.5 mg kg-1), TN (0.1 %) and MC at maize
maturity stage (8.7 %) compared to the not affected soil at 40 m away from the
Eucalyptus trees. In addition, the exch. Ca value at 1 m distance was most reduced and
was decreased by 4.1 (cmol (+) kg soil-1) compared to the control. The top dried field
soils at 0 to 220 cm distances were water repellent since the water drop penetration
time values were greater than 5 seconds. Moreover, Eucalyptus canopy intercepted
64.5 to 1579 lux of the light intensity resulting in poor performance of maize plants
under its shade. Plant height, yield, biomass and count decreased with distance to
Eucalyptus trees. This was not the case for Croton macrostachyus. The yield reduction
was in the range of 4.9 to 13.5 ton ha-1. Furthermore, the undergrowth density of
Eucalyptus was almost nil (24787 No.ha-1) as compared to that of coffee garden shade
(171102 No.ha-1). Altogether, our findings lead to a conclusion that Eucalyptus
plantation has a negative effect on sustainable cropping, soil, and water conservation
systems by decreasing TN, avail. P and exch. Ca through plant uptake, lowering the
soil moisture content both by its dense root system and by making the soil
hydrophobic and taking light away from the crop due to its dense and long canopy. It
has also been reported by local farmers that the dense Eucalyptus root network lowers
water tables and dries up springs. Full thesis.
Tegenu Ashagrie Engda:
Modeling rainfall, runoff and soil loss
relationships in the northeastern Highlands of Ethiopia, Andit Tid watershed.
Understanding the basic relationships between rainfall, runoff and soil loss are
vital for effective management and utilization of water resources and soil conservation
planning. Most of these relationships used in Ethiopia today are developed for
temperate climates and might not apply for a monsoonal climate. This study was
conducted with the main objective of modeling the relationship between rainfall,
runoff, and soil loss for climate conditions prevailing in Ethiopia. The study was
conducted in a small watershed located about 180 km North East of Addis Ababa.
Analysis of historical and field measured data sets, observation, previous studies and
discussion with the community were used to understand the hydrological and erosion
processes of the watershed. Soil infiltration rate and rainfall intensity analysis results
indicated as infiltration excess runoff is not a dominant runoff mechanism in the upper
un-degraded watershed. Effect of slope on runoff generation was also observed from
piezometers readings and test plot data. The watershed landscape was divided into
saturated, exposed rock and hillslopes areas after understanding of the hydrologic
behavior, and each modeled separately using the simple water balance hydrology
model. The model was tested for a total of ten years during both calibration and
validation. The model predicted the daily, weekly and monthly time steps stream
flows with reasonable accuracy. Although there is still substantial work to be done
before the model can be routinely applied in all catchments of the Blue Nile Basin
with different characteristics, it provides a good alternative to analyze different water
and land resources management approaches. Moreover, the new insight of Ethiopian
watersheds hydrology has a significant role on implying new land resources
management approaches. Stream sediment load trend analysis, observation and on site
discussion showed that surface runoff from the lower degraded watershed is the major
cause for soil erosion. A simple sediment model which relates surface runoff outputs
of the hydrology model with erosion was developed and used for four years daily data.
Sediment load prediction provided good insight into the main factors of erosion found
in the watershed. Surface runoff from the degraded lower part of the watershed
cultivated during the main rainfall seasons was found the main cause of sediment
transport to the stream. Further refining the sediment model by incorporating factors
that affect erosion will improve the efficiency of the model. Full thesis.
Haimanote Kebede Bayabil:
Modeling rainfall-runoff relationships and assessing impacts
of soil conservation research program intervention on soil physical and chemical properties at
Maybar research unit, Wollo, Ethiopia.
This study focuses on characterizing subsurface water flow and ground water table fluctuations in
response to rainfall that leads to saturation excess runoff, the basic principle of variable source
area hydrology. In particular, this study concentrates to develop a model that efficiently simulates
the location of saturated runoff areas and predict river discharge, which finally could help in
realistic planning of watershed interventions. Furthermore, the study assesses the impact of soil
conservation research program intervention on selected physical and chemical soil properties of
the study area. Long-term discharge and rainfall data was available at the watershed outlet and
for four test plots. In addition, 29 piezometers were installed in 2008 and water table measurements
were taken during the main rainy season. Based on major runoff mechanisms identified at the
catchment-level, a conceptual rainfall-runoff model was developed to compute runoff. The model
incorporates saturated excess overland flow from both bottomlands and subsoil exposed areas and
baseflow and interflow from the hillsides. The model was tested on a daily, weekly, and monthly
basis and fitted well the discharge data at the bottom of the watershed. In addition, the
distributed model output agreed well with the ground water table measurements. The watershed
was saturated (and produced runoff) in the flat areas near the river while the hillsides were
unsaturated with a perched water table that responded rapidly to rainfall. Data from test plots
showed that flatter areas produced more runoff than test plots at steeper slope areas. The model
has potential to predict runoff in ungauged basins but should be further tested to do so. On the
other hand, soil samples were tested for selected physical and chemical properties. The result
indicated that AP and % OC contents of the soil were found in lower amount than before/early
project intervention period, while the Db value has shown an increase. Full thesis.
Tegegne M. Tarekegne:
Sustainability of rural water supply and sanitation services in Ethiopia: A case study of twenty villages in Ethiopia.
Providing access to safe water and sanitation to combat poor health is an integral part of the strategy
to alleviate poverty in many countries according to the United Nations Development Assistance Framework
(UNDAF, 2006). Although sustainable water supply and sanitation services is a basic requirement for
development, there are only very few systems implemented over last 25 years in rural areas of Ethiopia
that are still functioning The objective of the research was to investigate the reasons behind the
low sustainability of rural water supply and sanitation services among different organizations each
with their unique approach. The research was conducted in the Libo Kemkem Woreda near Lake Tana
Ethiopia where a recent survey showed that two-thirds of constructed water points were not functioning,
and there was a low coverage of sanitation services. In this study a survey was undertaken covering
20 villages in which more than 400 respondents were interviewed examining a range of aspects such as
community participation, operation and maintenance practice, institutionalization of schemes,
community preferences and thoughts and major problems in water supply and sanitation services.
Results showed the sustainability of rural water supply and sanitation service depended on the approach
followed by the providers. Water supply systems were sustainable in which the community participated in
all stages of the project, selected members of the community were educated in operating the system and
spare parts and man power were available and manpower from the agency are special factors to sustain
the system; Latrine construction coverage and hygienic behavior was improved in villages where
volunteers and community facilitator teams were working. The survey indicated that the best
place to meet was on holidays in formal locations and not in church after church program.
Finally, organizations should focus on latrine construction, both household and communal latrines
around farming and grazing places.
Hussien Ali Oumer:
Land use and land cover change, drivers and its impact: A comparitive
study from Kuhar Michael and Lenche Dima of Blue Nile and Awash basins of Ehtiopia.
Land use and land cover change is driven by human actions and also drives
changes that limit availability of products and services for human and
livestock, and it can undermine environmental health as well. Therefore, this
study was aimed at understanding land use and land cover change in Lenche
Dima and Kuhar Michael of Amhara region, Ethiopia. Time-series satellite
images that included Landsat MSS, TM, ETM+ and ASTER, which covered
the time frame between 1972/3 to 2005, were used. Socio-economic Survey
and review of documents was carried out to understand historical trends,
collect ground truth and other secondary information required. Analysis of data
and other data was accomplished through integrated use of ERDAS imagine
(version 9.1), ENVI (version 4.3) and ArcGIS (version 9.2) software packages
along with Microsoft office analytical tools.
Remote sensing analysis revealed landscape level change of cultivated land
to have a net increase in Kuhar Michael, while a decline is found for Lenche
Dima. However, socio-economic surveys showed that household level
cultivated land has decreased from 1.2ha to 1ha and from 2.2ha to 1.8ha in
Kuhar Michael and Lenche Dima respectively, over the last 30years. Major
contributing factors included population increase, occurrence of drought, land
redistribution, and land degradation. Similarly, average land holding per
household has decreased from 1.6ha to 1.5ha and from 2.9ha to 2.2ha in
Kuhar Michael and Lenche Dima, respectively. This has jeopardized the
capacity of individuals to provide land for their siblings further leading to
landlessness, which is becoming a common phenomenon among rural youths.
In Kuhar Michael, dense shrub/bush land decreased at an annual rate of
-0.1%, while open shrub/bush land increased at a rate of 0.3%. As opposed to
this, dense shrub/bush land increased at a rate of 0.2% and open shrub/bush
land declined at annual rate of -0.2% in Lenche Dima. Grassland showed a
net decrease at a rate of -0.3% in Kuhar Michael due to conversion into
cultivated lands, while an increase with annual rate of 0.1% is found in Lenche
Dima as a result of implementation of watershed management practices.
Along with the observed decrease in vegetation cover, Limited availability and
extinction of some tree/shrub species is also reported and research is required
to quantify changes and understand the real impacts brought about.
Elias Sime Legesse:
Modeling Rainfall-Runoff relationships for the Anjeni watershed in the Blue Nile Basin.
Models accurately representing the underlying hydrological processes in the Nile Basin are necessary for
implementation of effective soil and water conservation practices. Despite this, most models currently
being used in the Nile basin have been developed for temperate climates and might not apply fully to
the monsoonal climates with distinct dry periods in the Nile basin. Recently a landscape based hydrology
model was developed for the monsoonal climates in the Ethiopian highlands by dividing the watershed in
areas that produce runoff and areas in which the all water infiltrates and eventually becomes interflow
or base flow. The model was calibrated and validated to predict the discharge of the whole Blue Nile
Basin. The objective of this study was to test the validity of the assumptions concerning the runoff
processes on a small scale. The study was carried out in the Anjeni Watershed in the Blue Nile Basin
for which discharge and rainfall measurements were available for an extended period. Thirty piezometers
were installed in four transects and the water table was measured during the rainy season. The
performance of the model was evaluated using three different techniques: coefficient of determination,
Nash and Sutcliff, and root mean square error (RMSE). Model calibration and validation indicated a
good fit between the observed and simulated discharge values. Values of coefficient of determination
for calibration were obtained to be 0.84, 0.89 and 0.95 for the daily, weekly and monthly time steps,
respectively. Similarly, Nash and Sutcliff values of 0.84, 0.83 and 0.96 were obtained respectively.
The runoff production mechanism in the Northern part found to be saturation excess although in practice
there is very little difference with infiltration excess runoff while in the southern, a combination of
saturation excess from the top and flow of water through cracks and openings with more percentage of the
flow is through the cracks and fissures.
Abrham Melesse Endalamaw:
Optimum utilization of ground water in Kobo valley, Eastern Amhara, Ethiopia.
Shortage of precipitation in Kobo valley limits the production of vegetables during dry
periods and the yield of cereals in the rainy periods. Irrigation from ground water
could enable farmers to cultivate more than once a year. Since pumping has an effect
on the ground water resources availability, effective management of water resources
using reliable calculation of historical groundwater balances at local and subwatershed
scales is required (Kendy et al 2004). We used CropWat 4 Window to
determine PET of the area and the Crop Water Requirement (CWR) of onion, tomato
and pepper, which are cultivated using irrigation during dry months; T-M and simple
water balance equations were used to quantify annual recharge to the water table and
water table status under different irrigation scenarios. Although irrigation from the
groundwater could ensure the food security of the area, different water management
scenarios showed that the ground water table will be declining as a result. Recharge
and water table calculations show that irrigation increases the recharge to the water
table but at the same time reduces the overall water table depth due to pumping. Water
table depth will not be depleted if irrigation follows the CWR of vegetables.
Calculations for future water table levels indicate that, if the current irrigation rate is
extended across all of the irrigable land in the area, the water table level will fall by 2
m per year. To protect against further water table decline, flashfloods should be
captured and used to recharge to the ground water.
Anteneh Zewdie Abiy:
Geological controls in the formations and expansions of gullies
over hillslope hydrological processes in the Highlands of Ethiopia, northern Blue Nile region.
The Northern Blue Nile River source region shallow depth highly weathered and fractured flood basalt
with several local structures and intrusive dykes. Volcanic morphological features and erosion has
formed smaller watersheds that exist within the Blue Nile basin. The control of the flow behavior of
both surface and subsurface water form a central pool for the sediment transported to the Sudanese
plain. The objective of this study is to define the geologic controls of hydrological processes aiding
in the formation and expansion of gullies along hill slopes in a micro watershed in the Blue Nile River
Twenty-four piezometers were installed, and soil hydrological behavior was studied in 17 ha of land in the Debremawi
watershed. Geologic features of the watershed include shallow depth, highly weathered and fractured basalt,
an impermeable layer and a local dyke. Layers of clay soil deposits are defined in the middle down slope
area of the watershed. The basalt is exposed in the upper slope area and underlies most of the watershed,
forming a fractured media aquifer. The impermeable layer consists of weathered silt sand clay pyroclastic
fall that has formed a compacted layer at the surface on the up hill.
The local intrusive basaltic dyke, located at the middle of the watershed and perpendicular to the flow
direction, has significant effect on the local ground water table distribution. Clay soil covering the
middle area of the watershed and overlying on the basalt layer confines the water in the fractured media
aquifer. Different sites with saturation excess runoff and infiltration excess runoff are identified to be
controlled by the combined effect of the local geological material and land use type.
Water head upstream of the dyke is near or above surface, but it is at a considerable depth below the
surface when downstream of the dyke.
Local saturation zones are subject to pore water pressure development and landslides. Saturated area
soils have little strength and result in soil slumps. High piezometric head and small scale earth movement
are identified in relation to the confining effect of the clay layer. Topographically controlled saturation
zones are also vulnerable to landslides and extensional soil cracking failures. The ultimate impact of the
local geology control is subsurface erosion features (soil pipes and tunnels) that develop into gullies.
Hence, land management practices should consider detailed studies of the local geologic materials and
structures. Incorporation of subsurface drainage mechanisms with the usual soil and water conservation
practices are of paramount importance for a better achievement in resolving the existing erosion and
Biniam Biruk Ashagre:
SWAT to identify watershed management options: (Anjeni watershed, Blue Nile basin, Ethiopia).
Ethiopia is known for its wealth of natural resources. These result in part from extreme
elevation variation. However, 5,000 years of land cultivation have degraded large
areas of the natural environment. Soil erosion affects 82% of the country. The rich
highland soil, which supports 80% of the total population, only covers 45% of the
country. In these highlands the soil is becoming less fertile; droughts are more
frequent and intense; and water resources are declining, due in part to the soil erosion.
The Anjeni watershed is located in the highlands in the Blue Nile Basin with an annual
soil loss of 18.33 tons/year/ha.
The existence of soil erosion in a watershed is an indication of unsustainable land
management practices. The objective of this study was to formulate sustainable land
management options that alleviate soil erosion in the Anjeni watershed. The SWATWB
model that simulates saturation excess flow was applied, and the result showed
that the Anjeni watershed is dominated by saturated excess flow from the shallow soils
rather than infiltration excess flow. The conventional SWAT model uses the SCScurve
number method which considers only infiltration excess flow. In contrast, the
SWAT-WB model simulates saturation excess flow in order to determine surface
runoff. Hence, SWAT-WB was used to investigate the flow and sediment processes in
the watershed and to compare different potential land management options to alleviate
The model SWAT-WB was calibrated for flow and performed well with a coefficient
of determination (R2) of 0.92 and Nash-Sutcliffe coefficient (ENS) of 0.91. The model
also performed well in simulating soil erosion on a monthly basis with the coefficient
of determination of 0.56 and the Nash-Sutcliffe coefficient of 0.55. The relatively
poorer performance of the model in simulating soil erosion can be attributed to a gully
in the watershed possibly contributing 30% of the annual soil loss from the watershed.
Model simulation suggests that the existing terraces are saving 2,046 tons/year of soil
loss. If further terraces are constructed, they could save an additional 932 tons/year.
Forestation of degraded areas and bush lands was found to reduce soil erosion by 333
tons/year. Zero-tillage technique for all fields except those covered with teff in the
watershed reduces erosion by only 45 tons/year. If gully rehabilitation work with a
90% erosion control practice is implemented in gullies, an additional 300 tons/year
would be saved. Combining foresting degraded lands and bush lands with
rehabilitation of gullies in Anjeni watershed is predicted to reduce soil loss from the
watershed by 630 tons/year. The impact of further construction of terraces on
productivity and its effect on the overall hydrological balance should be
experimentally investigated before being implemented and if it shows a significant
change, it can be practiced with some measures and innovations on the water
availability during the dry season.
Fikru Assefa Mengstie:
Assessment of adoption behavior of soil ad water conservation practices in the Koga watershed, Highlands of Ethiopia.
Land degradation is one of the major challenges in agricultural production in many parts of the world,
especially in developing nations like Ethiopia. Even though a number of soil and water conservation
methods were introduced to combat land degradation, adoption of these practices remains below
expectations. This research was conducted in the Koga watershed, near Lake Tana, in the catchment
of a recently constructed dam. It aimed to examine farmers’ views on land degradation and to assess
their adoption behavior of soil and water conservation knowledge.
Structured questionnaire survey and focus group discussion methods were applied to collect the necessary information
from farm households. A total of 100 households were interviewed and 282 plots and several fields were visited during
transect walks. The Tobit regression model was used for analyzing correlations among area, household, plot
characteristics and the adoption of three types of soil and water conservation practices. In addition, data were
analyzed using descriptive statistics and cross-correlation methods.
The results show that total area of plots, age of household head, education of household head, total number of
livestock and distance to market from household home are among the major factors that positively and significantly
influence adoption of soil and water conservation measures. Greater distance from home to farmland, smaller land to
labor ratio and larger family size are factors that decreased adoption. The data showed in addition that more
soil/stone bund terraces were implemented on steep land. Unlike in other studies in the region, sex of the
household head did not seem to make a difference in adoption of three different SWC practices.
Yidnekachew Ewnetu Ayalew:
Irrigation, Food Production and Consumption Pattern in Smallholder Rural
Conceptually, the benefits of irrigation are realized through improvements in
agricultural productivity. At household level, the agricultural production increases
could be followed by improvements in food consumption patterns. The goal of this
thesis is to examine the relationship between irrigation, food production and
household consumption patterns for the rural smallholders. A survey was undertaken
and information was collected on demographics, landholdings and agriculture,
irrigation, returns of crop cultivation, consumption behaviors, farmer perceptions and
experiences, and other related variables. The results show that the addition of
irrigation to the overall production system increases the agricultural income of
households but the amounts spend on food for each household did not increase as
consequence. However better dietary diversity was found on the consumption pattern
of the irrigated households with higher income. Integrated approaches are needed to
secure a healthy diet when the food supply of the family is increasing.
Habtamu Tilahun Kassahun:
Payment for environmental service to enhance resource use efficiency
and labor force participation in managing and maintaining irrigation infrastructure, the case of the upper Blue Nile basin.
Using the contingent valuation method, this research project explores how
irrigation beneficiary households in the Upper Blue Nile Basin of Africa value
irrigation water to enhance agricultural productivity. Research in this area is
important because soil degradation and sedimentation threaten the livelihoods of many
populations in the region. Furthermore, mitigation measures require continual large
investment costs both in terms of human capital and financial resources. The research
encompasses the analysis of data collected from 210 randomly selected household
heads in the Koga Watershed of the Upper Blue Nile Basin in Ethiopia.
The research reported herein has two major objectives. The first objective is to
explore the value of irrigation provided to households as an initial step towards the
development of a payment for environmental services (PES) program. Under this
broad objective, there are two specific goals. The first is to estimate households’
willingness to pay (WTP) to establish PES for upland soil and water conservation
measures that ultimately reduce sedimentation loading in the newly constructed
reservoir. The model results revealed that the aggregate expected WTP for the total of
7,000 hectares of irrigable land was 964,320 birr per year (9.65 birr equal $1 U.S.)
with a household utility-maximizing price of 192 birr per hectare of irrigable land per
year. The aggregate WTP was more than three times the annual budget allocated by
the Koga Irrigation and Watershed Management project to reduce sedimentation loads
(caused by upstream soil erosion) by 50 percent over the past 6 years. Thus, the
aggregate expected WTP by downstream users has a potential to compensate upstream
service providers and enhance resource use efficiency.
The second major objective of this research is to examine the magnitude and
determinants of labor supply behavior of farm households for the routine management
and maintenance of irrigation infrastructure in the Upper Blue Nile basin of Ethiopia.
For the total irrigable land area it is estimated that households could contribute an
estimated 468,784 person labor days per year. This would meet more than 30% of the
minimum annual labor requirement of the project for managing and maintaining of
irrigation infrastructures. A logit model analysis indicated that households’
willingness to contribute labor was influenced by education, age of the household
head, expectations about yields in irrigated agriculture, wealth of the household,
involvement in off-farm activities, time taken to walk to the nearest market, the
household’s dependency ratio and randomly assigned bid working days. Of these
determinant factors, an intervention measures for managing and maintaining irrigation
infrastructure through labor force participation should emphasize education about the
likely benefits of irrigated agriculture. To increase labor participation particularly for
new development projects, description of resource valuation scenario and future
benefits should be clearly explained to farmers. Furthermore, the number of persondays
allotted for conservation activities per hectare of irrigable land should take into
account the high elasticity of households’ willingness to contribute for the randomly
assigned bid working days.