Search

Payments for ecosystem services have recently been introduced into the ecosystem management landscape to counter ecosystem degradation. This study examines the experiences of sustainable use and management of watersheds using a compensation for ecosystem service model in the Koga watershed, Northern Ethiopia. The study primarily employed qualitative methods. Thirteen informants, chosen from a group of project implementers, were contacted for telephone interviews, and a document analysis was also conducted. Thematic approaches were employed to analysis the data. The study findings revealed that a project had been introduced to implement an innovative payment/compensation for ecosystem services (CES) scheme to manage watersheds and to alleviate poverty in the watershed. The scheme connected upstream and downstream communities and cooperatives through CES, earning praise for its effectiveness in combating dam siltation and watershed degradation. The initiative also established various enabling conditions, such as capacity building, bylaw formulation, and payment procedures for beneficiary communities. However, the CES scheme still has a long way to go to deliver the anticipated positive impacts on local livelihoods and watershed management. It is believed that a comprehensive legal framework, a stable political and social environment, and sustainable financing mechanisms are crucial for the success of any CES project. Therefore, Ethiopia should strive to meet these requirements to ensure that any future CES projects are designed and implemented sustainably. [ABSTRACT FROM AUTHOR]

This study aimed at assessing the long term impacts of watershed management interventions and scenarios on sediment export reduction in the data-scarce region of the Yezat watershed in north-west Ethiopia. The modified ecosystem services valuation model (InVEST) was employed to evaluate the amount of sediment export in the watershed. Different watershed management intervention scenarios were applied to evaluate the effectiveness of watershed management interventions on sediment export reduction. The results of the study showed that the mean annual sediment yield was 35 tons ha yr in 20000, due to the expansion of cultivated land and built-up area. Conversely, it decreased from 35 ton ha yr in 2000 -18.4 ton ha yr in 2021 due to watershed management interventions. On the contrary, moderate, severe, and very severe categories of sediment export intensity were high in 2000. But it decreased in 2021 due to watershed management interventions. The mean annual sediment export in the baseline scenario (BS) was 35 tons per year, which was reduced to 13.39 tons per year, 3.46 tons per year, and 1.17 tons per year in the reforestation scenario, soil/stone bund, and integrated scenarios, respectively. The result revealed that areas covered by high sediment severity classes were reduced. [ABSTRACT FROM AUTHOR]

The rapid deterioration of the upper Akaki catchment natural environment has led to an increasing impact not only on the watershed ecosystem but also the livelihood and the general well‐being of the local community. As a result, the water supply is becoming a problem for Addis Ababa and its surrounding residents. This may lead to a greater willingness to pay and cooperate in initiatives to protect the watersheds. Therefore, a market‐based instrument and participatory arrangements are critical for resolving socioecological problems. This research aimed to demonstrate a need for an incentive‐based watershed conservation approach that can be used to support nature conservation through long‐term financial investments in the central watersheds and elsewhere. To support the market‐based intervention, sealable ecosystem services and cost–benefit analysis, as well as relevant stakeholders, institutions, and legal frameworks, were assessed. The prime factors for designing market‐based approaches to halt biodiversity loss and reversing ecological processes are discussed. A domestic water tariff increase of ETB 1 per m3 (US$ 0.08) could raise approximately US$ 3.24 million annually for watershed management, which could compensate smallholder farmers' annual opportunity costs for crop and livestock forage loss. Furthermore, the practice could help to abate biodiversity loss, improve the local economy, and accelerate the implementation of global biodiversity targets. Integr Environ Assess Manag 2024;20:965–974. © 2023 SETAC Key Points: The rapid deterioration of watersheds is impacting the ecosystem and the well‐being of people.Water supply issues prompt collaboration on a watershed protection program.Raising financial resources could compensate farmers.Watershed management accelerates meeting biodiversity targets. [ABSTRACT FROM AUTHOR]

In developing countries, research evidence on the socio-economic impact is a crucial issue in motivating and encouraging community-based restoration of degraded watershed ecosystems. This paper focuses on exploring the socio-economic impacts of rehabilitating a watershed area in two villages (kebeles) using two independently pooled cross-sectional data sets. 240 households were selected at random to provide the data. Half of the households (120) were randomly chosen from the records of the rural land and agricultural development office in 2007 and the other half (120) were randomly selected and interviewed in 2022 using semi-structured questionnaires. Our results show that the contribution of the restored area to the economy of the local communities dramatically increased between 2007 and 2022. The main economic activities encountered in the restored area are fuelwood collection, the harvesting of construction wood, collecting grasses, and harvesting fodder, which are practiced by 75%, 68%, 59% and 41% of sampled households in 2022, respectively, while the same activities were practiced by 5%, 0%, 0%, and 2.5% households in 2007, respectively. Rehabilitation intervention also created job opportunities, and strengthened social networking among local households. These findings can help government and non-government stakeholders those implement ecosystem restoration by enhancing community-based rehabilitation of watersheds. [ABSTRACT FROM AUTHOR]

The Soil and Water Assessment Tool (SWAT) and the Geographic Water Erosion Prediction Project (Geo-WEPP) were applied to compare modeling of annual runoff and sediment yield in the Agewmariam watershed, eastern Amhara Region, Ethiopia. Spatial and temporal data distributions were required as inputs to run both models. Soil texture and other soil properties were measured in the field and in the laboratory, and soil maps were generated from global digital soil maps. Land use maps were created by manually digitizing Google Earth images. Watersheds were defined using watershed DEMs and gradient maps were created for each runoff event. Runoff samples were collected and analyzed for sediment concentrations in the laboratory; average annual runoff and sediment volumes were estimated using the WEPP and SWAT models. The results were satisfactory compared to the observed values, with R2 values of 0.86 and 0.91 for the SWAT and WEPP models, respectively, and NSE values of 0.54 and 0.71 for the monthly runoff. The estimated annual mean runoff and sediment yield at the watershed outlets were 65.54 mm, 146.14 mm, 43t/ha/yr and 41.7t/ha/yr for the WEPP and SWAT models, respectively. Several sub watersheds were determined to be susceptible to soil erosion and were prioritized, so more attention was given to this area to reduce runoff and soil erosion. Therefore, the SWAT and WEPP models were suitable for estimating annual runoff and sediment volumes. Sediment yields simulated from both models were high and alarming and far exceeded the allowable rate of soil loss. [ABSTRACT FROM AUTHOR]

While the availability of "big data" on biophysical parameters through citizen science and/or from public/private sources is expected to help in addressing data scarcity issues, there is little understanding of whether and/or how such data will improve watershed simulations. This research aimed to evaluate whether improvements in resolutions of Digital Elevation Model (DEM) and soil data will enhance streamflow and sediment yield simulations and thereby improve soil and water management decisions. The study was conducted in two different-sized watersheds (Anjeni and Gilgel Abay with ~ 1 km2 and ~ 1655 km2 area, respectively) in the Upper Blue Nile basin in Ethiopia. Effects of DEM and soil data resolutions on streamflow and sediment yield were evaluated using the Soil and Water Assessment Tool (SWAT). The results showed that the effect of DEM and soil data resolution on streamflow and sediment yield simulation was scale dependent finer resolution DEM and soil datasets improved streamflow and sediment yield simulations in the smaller Anjeni watershed, whereas DEM resolution had no effect in the bigger Gilgel Abay watershed. Small watersheds are often used to understand watershed processes, and thus the use of finer-resolution spatial data for watershed simulations could result in better results. Findings from the smaller Anjeni watershed suggested that the combined use of finer resolution DEM and soil data could potentially improve sediment yield simulations although the lack of observed sediment yield data did not allow verification of this at the larger Gilgel Abay watershed. [ABSTRACT FROM AUTHOR]

Integrated watershed management is the method of overseeing human exercises and characteristic assets on a water shed basis, taking into consideration social and financial concerns. It is an ever-evolving hone including the administration of arrive, water, biota, and other assets and it requires involvement of strong institutions at the grass root level. Most watershed projects were not successful due to a lack of effective community participation. The objective of this study was to evaluate the contribution of community participation in integrated watershed management schemes in the Dandi lake watershed (Ethiopia) for long-term water resource conservation initiatives and short-term livelihood activities that enables the communities of the study area to meet their needs. Questionnaires, FGD, key informant interviews, personal observation were used as data collection tools. The collected data were organized and categorized according to the intended objectives and analyzed in qualitative and quantitative methods. The result of the study showed that role of community participation in participatory watershed management was examined by involvement in different management phases, 65.1% were involved only in the implementation stage, only 27.6% of respondents confirmed as they involve in all stages, 5.9 and 1.3% of sampled respondents witnessed as they are only involved in planning and mapping stage of watershed management. This study revealed that community participation in water shade management was hindered due to shortage of resources, interest, and previous experience, as well as peer pressure. In the meantime some successful efforts have been made on different land uses meant to reduce natural resource degradation and food security problems. These efforts include, contribution of delivered extension service, infrastructure provision and maintenance. The study also realized and proved the existence of unused development potential to improve the livelihood situation of the watershed community. This study came up with a good managerial implication, typically, it enhances Community engagement status by increasing its visibility and understanding of issues and empowers communities to have a say in decisions that affect their lives, cities and neighborhoods. The watershed management guidelines have to be clear to the community. [ABSTRACT FROM AUTHOR]

Watershed development is part of a poverty reduction and environmental conservation initiative in Ethiopia. The study evaluates the impact of project-supported and community-based watershed development (WSD) interventions on households' food security status and identifies the factors that affect WSD participants. A propensity score matching (PSM), a household food balance model (HFBM), a geographic information system (GIS), and a Digital Elevation Model (DEM) were employed to analyze data. The PSM model result revealed that participation in a project-supported WSD had a more significant effect on household food security than the community-based WSD. The average treatment effect for the treated (ATT) was 3845.02 Kcal, while the average treatment effect for the control group (ATE) was 3037.85 Kcal, depicting a significant difference between them. Changes in land use and land cover in the study watersheds imply that agricultural and degraded land patterns decreased, whereas grazing land, bushland, wetland, and plantation land patterns have increased in project-supported watersheds over the study period. On one hand, the main socio-economic drivers that positively impacted the food security status of the WSD participation were land size, credit access, livestock ownership, and training. On the other hand, market distance and distance from farmers' training centers have a significant and negative impact on the status of the households' food security. The study concludes that project-initiated WSD intervention has a crucial impact on achieving household food security. Priority should be also given to increasing the productivity of land, increasing access to credit services, improving livestock ownership, and providing veterinary services. [ABSTRACT FROM AUTHOR]

In Ethiopia, watershed management interventions have been implemented since the 1980s to curve land degradation and improve the agricultural productivity of smallholder farmers. However, little effort has been made to investigate the impacts of watershed management on land use/cover changes and landscape greenness. Thus, this study was conducted to assess the long-term impacts of watershed management on land use/cover changes and landscape greenness in the Yezat watershed. Landsat images for 1990, 2000, 2010, and 2021 were employed and analyzed to produce maps of the respective years using GIS and remote sensing techniques. Data from satellite images, coupled with field observation and the socio-economic survey, revealed an effective approach for analyzing the extent, rate, and spatial patterns of land use/cover changes. Normalized difference vegetation index (NDVI) was also employed to detect vegetation greenness. The results of the study show that between 1990 and 2021, the built-up area, plantation, natural forest, shrubland, and grasslands were increased by + 254 ha, + 712.3 ha, 196.3 ha, + 1070.8, and + 425.3 ha respectively due to watershed management interventions. Conversely, cultivated land was decreased with a rate of − 2658.7 ha, in the study area. However, the reverse is true between 1990 and 2000 due to large-scale land degradation. Besides, the result of the study also shows that a low landscape greenness value (− 0.11) was observed between 1990 and 2000, and a high landscape greenness value (+ 0.2) was observed between 1990 and 2021. The observed change in landscape greenness in the watershed was due to the change in shrubland (+ 1070.8 ha), grassland (+ 425.3 ha), plantation (+ 712.3 ha), and forestland (+ 196.3 ha) covers between 1990 and 2021 years. Such observed changes in land use land covers, landscape greenness, and cultivated land in the study watershed have important implications for the improvement of soil moisture, soil fertility, biodiversity, groundwater recharge, carbon sequestration, soil erosion land, crop yield, and ecosystem services. [ABSTRACT FROM AUTHOR]

Climate variability is emerging as a major threat to Ethiopian pastoralists. Increased vulnerability to climate variability not only wrecked pastoralists' livelihoods but also eroded scarce resource management practices. The objective of this research was to investigate the status of pastoralists' vulnerability to climate variability in the Burkitu watershed in Southern Ethiopia. The Livelihood Vulnerability Index (LVI) was used in the study to assess household vulnerability to climate variability through direct household surveys. To select 340 sample respondents, multistage sampling techniques were used. Data on socioeconomic and biophysical attributes were collected and combined into indices, from which vulnerability scores for each watershed unit were calculated. There was some variation in the level of vulnerability across watershed units. The outlet had a higher vulnerability score (0.73) due to the pastoralists' higher level of exposure and low adaptive capacity status. The upper watershed unit was identified as having a lower level of vulnerability with a score of (0.19), whereas the middle watershed unit has an intermediate level of vulnerability (0.44). Therefore, any interventions aimed at improving pastoralists' livelihood resilience should concentrate on addressing characteristics that exacerbate households' exposure to climate variability, thereby increasing adaptive capacities. [ABSTRACT FROM AUTHOR]

The Soil & Water Assessment Tool (SWAT) has been calibrated over a 33-year period to evaluate the Gojeb watershed's hydrological processes, sediment yield with downstream loading to the Gibe III dam, and erosion hotspot locations. Best management practices (BMPs) were run through the model to simulate the effects of watershed intervention scenarios on sediment yield and runoff. Simulation results of BMP intervention were compared with the reference and worst-case scenarios. The simulation of sediment production indicates a clear growing trend. Temporally, the maximum amount of sediment transported out of the watershed is experiential from June to September, and the minimum is in February. A plainly defined similar orientation is observed between precipitation, surface runoff, and sediment load in the landscape. Spatially, the maximum sediment transported out of the watershed is from agricultural landscape units with a slope of over 50%, annual precipitation above 1592 mm, and surface runoff over 151 mm. This signifies that the watershed is under serious threat from erosion due to vegetation loss, steep slope farming, and high surface runoff. Gibe III is a 243-m high roller compacted gravity dam built on the Omo-Gibe River basin in Ethiopia for hydroelectric power and downstream flood control. It is one of Africa's tallest dams, with an annual electric output of 1870 MW that began operation in 2016. Thus, Gibe III could see a loss of storage capacity due to higher-than-expected sedimentation resulting from worsening environmental degradation, which implies that the beneficial uses that depend on this dam — electricity production, regulated irrigation water supply, and flood control — will decline with significant economic losses. Despite that, selected sustainable land management interventions and the application of BMPs to critical erosion-prone hotspot areas can support the overall reduction in total sediment yield and surface runoff. [ABSTRACT FROM AUTHOR]

Remote sensing and GIS technology were very helpful to determine an appropriate location of freshwater storage in Amhara, Ethiopia. The techniques were used to investigate the impact of lithology, surface geomorphology, slope parameters, drainage flow, drainage density, lineament density, land cover parameters on relief, and aerial and linear features and to understand their interrelationships. Morphometric parameters such as mean stream length (Lsm), stream length ratio (RL), bifurcation ratio (Rb), mean bifurcation ratio (Rbm), relief ratio (Rh), drainage density (Dd), stream frequency (Fs), drainage texture (Rt), form factor (Rf), circularity ratio (Rc), and elongation ratio (Re) were calculated. Spatial maps of morphometric parameters were produced by using AHP (analytical hierarchy process) of ArcGIS 10.3. Final priority map was generated by the overlay of those parameters with five categories of poor (16.6%), low (41.63%), moderate (29.61%), high (8.88%), and very high (3.28%) storage locations. The map showed that this study area belonged to the low to moderate storage location. The results exhibit precision-based assessment of the suitability for the dam construction sites of 6, 7, and 9 sub-basin zones. The outcome of this study strengthens the knowledge of geospatial analysis for water resources vulnerability and also allows policymakers in this drought-prone area to sustainably manage water supplies. [ABSTRACT FROM AUTHOR]

Background: Land-use and land-cover (LULC) change is among the dynamic environmental and ecological factors for monitoring and facilitating the developmental strategies to balance conservation and conflict of resource uses. This study aimed to analyze LULC changes that have occurred during 1988-2018 and its prediction for 2040-2060 periods. Methods: LULC changes were analyzed using geographic information system Landsat and predicted by CA-Markov model. Result: The results of this study confirmed that cultivated-land and rural-settlement, bare-land, built-up-area and waterbody have increased at an annual rate of 23.1, 2.2, 0.8 and 1.1 ha/year but forestland, bushland and grassland have decreased at an annual rate of 14.4, 4.1 and 8.7 ha/year, respectively. It is projected that the increase in cultivated-land, bare-land, built-up-area and waterbody but decreases the forestland, grassland and bushland. Expansion of agriculture and deforestation showed increasing trend on both previous and predicted LULC changes with upcoming expansion of bare-land due to major driving factor of population growth. Thus, well integrated landscape planning and reliable predictions for future LULC are needed to reduce the deterioration of environment. [ABSTRACT FROM AUTHOR]

This study was conducted to quantify, analyze and map soil erosion risk areas using remotely sensed data and GIS-based Revised Universal Soil Loss Equation (RUSLE) model at Mihtsab-Azmati Irrigation Dam Watershed, Northern Ethiopia. Based on the result, the watershed has potential soil erosion risk which ranges from 0 ton hectare−1 year−1 to 2980.12 ton hectare−1 year−1 with an average annual soil erosion rate of 110.06 ton hectare−1 year−1. From the entire watershed area, only 27% of it has a soil loss a value less than 15 ton hectare−1 year−1 which is relatively categorized under low soil erosion risk, while the remaining area (73%) experiences moderate to very high soil loss rates. A large area (50.7%) is under high to very high soil loss (>50 ton hectare−1 year−1). The majority of the study watershed area experiences a very high soil erosion rate and this could be a major threat to the new irrigation dam constructed at the outlet of the watershed due to the sedimentation problem, which could decrease the economic lifespan of the dam. Hence, from the conservation perspective, a large proportion of the upper watershed area requires immediate and appropriate soil conservation measures. [ABSTRACT FROM AUTHOR]

In assessing the challenges and opportunities of small-scale irrigation in a watershed, comprehensive assessment of all governing factors are important to get optimized, reliable and timely information on the area. This study was conducted in Abagerima watershed, Lake Tana sub-basin, Ethiopia. The aim of the study was to assess the level of suitability and potential of the watershed for small-scale irrigation using an integrated approach by Remote Sensing (RS), Geographic Information System (GIS), land and socio-economic survey. Land assessment was performed based on the Food and Agricultural Organization land evaluation techniques employing multi-criteria decision rule technique that integrates major determinant factors to practice irrigation at the smallholder level. Determinant factors including, slope, land use, soil type, water availability and accessibility were considered. For each factor, raster based spatial data were produced. The relative landscape suitability of the watershed was characterized as highly suitable, moderately suitable, marginally suitable and unsuitable. A cumulative suitability rank was determined using ArcGIS 10.2 software. Finally, a suitability map was produced. The result shows that about 20% of the watershed could be used for irrigation. However, only 2% of the watershed was irrigated during this research was conducted. This implies that about 18% of the watershed that could potentially be irrigated was not yet exploited and need to be further developed. The major challenges that hinder irrigation development in the watershed were land degradation, land fragmentation and lack of appropriate technology for water resource utilization and exploitation. Hence, it has to be recommended that water utilization efficiency should be improved through the creation of awareness, particularly on the introduction and use of better water conveyance and application technologies. [ABSTRACT FROM AUTHOR]

This study provides local perspectives on water use and conservation of Lake Ziway and its watershed in Ethiopia. Past and present water use, management and conservation efforts are investigated, and causes to the lake's current degradation are presented. The study is based on empirical data gathered through face-to-face interviews with experts from federal, regional and district state offices, research center, and local economy and conservation groups. The results show that the water quality and water level of Lake Ziway have been decreasing due to anthropogenic factors. The main causes are attributed to uncontrolled water abstraction from the lake, discharge reduction from feeder rivers, siltation due to deforestation-induced soil erosion in the watershed, and effluent discharges from floriculture industries as well as agrochemical runoff. Water use and discharge influx is not regulated or planned. A good number of interviewees perceived that the state's effort to address the problems of Lake Ziway and its watershed is weak. This study contributes to the understanding of the local socio-ecological coherences and environmental problems Lake Ziway and its watershed are facing. It also provides firsthand information that can contribute to the development of long-term sustainable water use and conservation strategies for the lake and its watershed, which could also be applied to other lakes in Ethiopia, and beyond. [ABSTRACT FROM AUTHOR]

While the availability of "big data" on biophysical parameters through citizen science and/or from public/private sources is expected to help in addressing data scarcity issues, there is little understanding of whether and/or how such data will improve watershed simulations. This research aimed to evaluate whether improvements in resolutions of Digital Elevation Model (DEM) and soil data will enhance streamflow and sediment yield simulations and thereby improve soil and water management decisions. The study was conducted in two different-sized watersheds (Anjeni and Gilgel Abay with ~ 1 km 2 and ~ 1655 km 2 area, respectively) in the Upper Blue Nile basin in Ethiopia. Effects of DEM and soil data resolutions on streamflow and sediment yield were evaluated using the Soil and Water Assessment Tool (SWAT). The results showed that the effect of DEM and soil data resolution on streamflow and sediment yield simulation was scale dependent finer resolution DEM and soil datasets improved streamflow and sediment yield simulations in the smaller Anjeni watershed, whereas DEM resolution had no effect in the bigger Gilgel Abay watershed. Small watersheds are often used to understand watershed processes, and thus the use of finer-resolution spatial data for watershed simulations could result in better results. Findings from the smaller Anjeni watershed suggested that the combined use of finer resolution DEM and soil data could potentially improve sediment yield simulations although the lack of observed sediment yield data did not allow verification of this at the larger Gilgel Abay watershed., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Information on use/land cover change is important for planners and decision makers to implement sustainable use and management of resources. This study was intended to assess the land use land cover (LULC) change in the Koga watershed. The MSS of 1973, TM images of 1986, 1995 and 2011 were used together with survey and demographic data to detect the drivers of land cover changes. The result revealed that a remarkable LULC change occurred in the study area for the past thirty eight years. The area of cultivated and settlement has increased by 7054.6 ha, while, grass and bush lands decreased by 4846.5 and 3376 ha respectively. Wetland also declined from 580.2 ha to 68.3 ha. The growing demand for cultivable land and fuel wood were the major causes to the deterioration of grass and bush lands. Hence, the appropriate land use policy should be employed to sustain available resource in the watershed. [ABSTRACT FROM AUTHOR]

This paper firstly analyzes the land use - land cover (LULC) in Lake Ziway watershed (Ethiopia) and quantifies the changing patterns from 1973 to 2014 using Landsat images. Secondly, the paper estimates sediment yields using the Soil and Water Assessment Tool (SWAT model). It also assesses and estimates water abstraction from Lake Ziway using survey data. The study shows that the conversions from woodlands into agricultural lands and settlement areas are the major detected LULC changes. Of the total area of the watershed, agricultural lands and settlement areas together increased from 57% in 1973 to 75% in 2014 at the expense of woodlands whose areas decreased from 26.16% to 6.63% in the study periods. The study also shows that water abstraction and sediment loads are increasing at Lake Ziway watershed. The major driving forces behind these LULC changes and the impacts on the lake natural condition are anthropogenic factors such as population growth, land policy changes and deforestation. Increasing demands for more land and water resources, i.e., land for settlements and cultivation, wood for fuel and charcoals, and water for irrigation and municipal water supply, are the underlying causes for the observed changes on the watershed resources. Thus, if the existing scenarios of human pressures are left neglected without management interventions, severe watershed degradations will continue to further affect the watershed's resources including the hydrology. Therefore, responsible government institutions should start mobilizing the local communities along with providing financial and material supports for watershed rehabilitation through afforestation and soil and water conservation activities. Additionally, the free-access practices for water use should be replaced by user-charge policy to regulate water abstractions in order to adequately sustain the water level of Lake Ziway and its feeder rivers. In this respect, this study provides firsthand information to policy makers and planners to put in place a comprehensive land and water use plan and regulations against the unruly human actions in the watershed before irreversible losses might happen to Lake Ziway and its watershed resources. [ABSTRACT FROM AUTHOR]

This study examines the morpho-tectonic settings of the drainage system in the northwestern Ethiopian plateau by focusing on the Tekeze River. The plateau is underlain by Precambrian crystalline rocks, overlain by EOCENE and Late Oligocene basalts. An attempt is made to study the underlying geology of Tekeze river basin and its significance in morphometry e.g., linear, relief and areal parameters. Further to analyze the influence of topography and geology on morphometry integrating Remote Sensing data and GIS techniques. The study used ArcGIS software for the computation, delineation of the boundary and morphometric analysis of the watershed using topographical maps and SRTM DEM data. Total area of watershed is 84738.55 Sq. Km. Total numbers of 18 rock types were mapped out in watershed and most of the area is covered by the Basalts (36.01%). The steep relief explained by complex geological history represented in major geological terrains starting from Archaen (about 40 billion years ago) till Quaternary period (about 11 thousand years ago) and marine sediments occurring in the western part. The Quantitative analysis of drainage network shows that the river is having the dendritic pattern. The drainage density is low which indicates the coarse drainage pattern. Drainage texture, stream frequency and the form factor of the watershed are 0.04, 0.12 and 0.69 respectively. The bifurcation ratio of the watershed ranges from 1.68 to 12 and the elongation ratio is 0.78 which refers to high relief of the study area. The mean bifurcation ratio of the whole watershed is 13.71 indicating that the drainage pattern is greatly influenced by geological structures. [ABSTRACT FROM AUTHOR]

Controlling soil erosion is important for maintaining land productivity and reducing sedimentation of reservoirs in the Ethiopian highlands. To gain insights on sediment loss patterns, magnitude of peak sediment events, and their contribution to annual loads, hydrometric and sediment concentration data were collected for five years (2010 - 2014) from the 95-ha Debre Mawi and four nested catchments (located 30 km south of Lake Tana). Soil and water conservation practices (SWCPs) consisting of soil bunds with 50-cm-deep furrows were implemented in the third year, which made it possible to examine the effects of SWCPs on peak sediment loads. The results show that a 10-min event causes soil loss of up to 11·4 Mg ha−1, which is 22% of the annual sediment yield. Thirty to seventy-five percent (up to 30 Mg ha−1day−1) of the sediment yield was contributed by the greatest daily flow in each year. The contribution increases to 86% for the two largest daily flows. SWCP interventions reduced sediment loss by half but did not affect the relative contribution of peak events to annual loads. Because of gully erosion, peak sediment loads at the outlet of the entire catchment were greater (up to 30 Mg ha−1day−1) as compared to the nested catchments without gullies (0·5 to 8 Mg ha−1day−1). Consequently, to reduce sediment loss, conservation measures should be designed to decrease runoff during large storms. This can be attained by deepening furrows on unsaturated hillsides and reducing the entrainment of unconsolidated sediment from failed gully banks. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Increasing population and intensification of agriculture increase erosion rates and often result in severe land degradation and sedimentation of reservoirs. Finding effective management practices to counteract the increasing sediment load is becoming increasingly urgent especially in the Ethiopian highlands where the construction of the hydroelectric Grand Renaissance Dam on the Blue Nile is underway. In this paper, we examine the results of 9 years of a watershed experiment in which discharge and sediment losses were observed in the 113 ha Anjeni watershed of the Blue Nile Basin. The study period encompasses conditions before, during, and after the installation of graded Fanya- Juu ('throw uphill' bunds) soil and water conservation practices (SWCP), which had the ultimate goal of creating terraces. We use a saturation-excess runoff model named the parameter-efficient distributed model as a mathematical construct to relate rainfall with discharge and sediment losses at the outlet. The parameter-efficient distributed model is based on landscape units in which the excess rainfall becomes direct runoff or infiltrates based on topographic position or hardpan characteristics. Deviations in this rainfall-discharge-sediment loss relationship are ascribed to the changes in infiltration characteristics caused by SWCPs on the hillslopes. With this technique, we found that in the Anjeni basin, the Fanya-Juu SWCPs are only effective in increasing the infiltration and thereby reducing the direct runoff and sediment concentrations in the first 5 years. At the end of the 9-year observation period, the direct runoff and sediment concentrations were barely reduced compared to the levels before SWCP were installed. In addition, we found that the model structure based on landscape units was able to represent the varying runoff and erosion processes during the 9 years well by varying mainly the portion of degraded land (and thereby representing the effectiveness of the Fanya-Juu to reduce runoff by increasing infiltration). [ABSTRACT FROM AUTHOR]

This paper synthesizes the spatial and temporal relationship between forest cover and water, as well as its implications for food security in the northwestern highlands of Ethiopia. Different studies addressing the topic of land cover and hydrology have been reviewed. Analyses of 20–40 year long time series showed little and inconsistent relationships between forest cover change and hydrology on meso-scale (100–1000 km 2 ) watersheds. Spatial studies, however, showed stronger relationships between land cover and low flow features such as grasslands and woodlands. Interviews with local communities suggested land cover change impacts are more pronounced at smaller scale (<100 km 2 ) watersheds; which is consistent with observational studies on small scale watersheds and farm level plots. The stronger relationships between forests and hydrology at smaller scales suggests land management policies should be oriented to farm level conditions, where water is vital for the food security of subsistence farmers who comprise 86% of the population in the highlands. [ABSTRACT FROM AUTHOR]

Community perception of forest-water relationship was gathered using participatory rural appraisal tools in four watersheds of the Blue Nile River Basin in Ethiopia. These were compared and contrasted with the observational records of forest cover and water flow. Upstream and downstream communities were assessed separately to check for differences in perception based on location within a watershed. The key result of the study was that people in the study watersheds had a range of perceptions about the forest-water relationship which were watershed specific. The perceptions were generally consistent with observational evidence from the same watersheds. This study highlighted the need for locale-specific approaches to land and water management in the Basin, as well as the potential value of using community perceptions to complement the observational records which can have spatial and temporal limitations. [ABSTRACT FROM AUTHOR]

Abstract: Information on soil properties and distribution is critical for making decisions with regard to crop production and mitigating land degradations. A reasonable way of deriving the information is using proxy environmental characteristics that have demonstrated relationships with soil properties. A field study was conducted to evaluate the relationship between topography, land use and soil properties. Three slope classes were considered and a total of three pedons, one on each slope class, were opened and described at the Ele watershed in southern Ethiopia. Soil samples collected from identified horizons of each pedon were analyzed for physicochemical properties. Additionally, random soil samples were collected from adjacent cultivated, grassland and forest soils; and three composites were made for each land use type within the three slope classes. All three pedons showed remarkable variability in physical, chemical, and morphological characteristics of the soils. The field as well as laboratory textural class determinations revealed the dominance of clay fraction in the soils. The existence of buried horizons with abrupt textural as well as sharp changes in color both in dry and in moist showed the occurrence of lithological discontinuity. Both soil pH and EC were low for steep slope and highest for the middle slope class, whereas the organic carbon (OC), total N (TN) and available P decreased down the slope. Gentle and moderate slope classes had the highest exchangeable bases, while the steep slope had the lowest owing to the removal and deposition of exchangeable bases by water erosion. The chemical properties of the soils were also significantly affected by land use. The highest values of both pH and EC were obtained in cultivated land, whereas grassland had relatively more OC, exchangeable Ca, Mg, K and available micronutrients than the other land use types. [Copyright &y& Elsevier]

Forty-five years (1960-2004) of hydrological data from 12 watersheds in the Abbay Basin, Ethiopia, were tested for possible trends over the entire time series and differences in medians (step-wise changes) between three sub-periods. The classification of the sub-periods was based on the major political changes in 1975 and 1991. Variables investigated were rainfall ( P), total flow ( Q), high flow ( Q), low flow ( Q), low flow index (LFI) and run-off coefficient ( C). Data were checked for outliers, errors and homogeneity. Trend was tested after serial and cross-correlation tests. The data for each variable were serially uncorrelated from 1 to 10 lag years. There were five globally significant trends out of 50 test cases and 36 significant step-wise changes out of 180 tests. The majority of the significant changes were watershed specific. Run-off coefficient was the single variable showing a consistently increasing trend and stood for ca. 25 % of the total significant trends and step-wise changes. Half of these changes occurred after 1991. We concluded that despite the land use policy changes in 1975 and 1991, as well as the long-term soil degradation, the hydrological regime was quite stable over the 45-year period, with the exception of an increase in the run-off coefficient in the latter part of the run-off record in some watersheds. [ABSTRACT FROM AUTHOR]

Understanding the relationship between topography, hydrological processes, and runoff source areas is essential in engineering design, such as predicting floods and implementing effective watershed management practices. This relationship is not well defined in the highlands with a monsoon climate and needs further study. The objective of this study is to relate topographic position and hydrological response in tropical highlands. The research was conducted in the Debre Mawi watershed in the northwest sub-humid Ethiopian highlands. In the monsoon rain phase of 2017 and 2018, groundwater depth, infiltration rate, and surface runoff were monitored at the upslope, midslope, and downslope positions. Surface runoff rates were measured in farmer fields through distributed V-notch weirs as estimates of positional runoff. Average water table depths were 30 cm deep in the downslope regions and 95 cm in the upslope position. The water table depth affected the steady-state infiltration rate in the rain phase. It was high upslope (350 mm h−1), low midslope (49 mm h−1), and zero downslope. In 2017, the average runoff coefficients were 0.29 for the upslope and midslope and 0.73 downslope. Thus, topographic position affects all aspects of the watershed hydrology in the humid highlands and is critical in determining runoff response. [ABSTRACT FROM AUTHOR]

The article presents a case study which investigates the impact of soil and water conservation measures on catchment hydrological response in north Ethiopia. It mentions that the soil and water conservation measures include the construction of dry masonry stone bunds, check dams, and the establishment of woody vegetation. It notes that the indicators for improved water supply in the manage catchment include emerging wells and irrigation.

• The SWAT model is developed in the Genale watershed to determine sediment yield and SDR. • Identification of soil erosion hot-spot regions at sub-basins/HRUs scales within the catchment. • Evaluating the influence of LULC & slope variation on sediment yield at HRUs scale. • Sub-basins/HRUs prioritization based on the evaluated catchment SDR and sediment yield. • Estimating spatiotemporal variation of sediment yield in the watershed helps decision-makers. Erosion of the topsoil is a serious environmental problem worldwide that critically alarms agricultural and upland areas. Most wetlands, rivers, and reservoirs are losing their capacity because of sediment deposition into the water body from the upstream of watersheds, as they were not managed. Soil and Water Assessment Tool (SWAT) model is used to simulate streamflow, sediment load, & identify spatiotemporal variability of the sediment yield and sediment delivery ratio (SDR), point out erosion-prone area, and prioritize sub-basins/hydrologic response units (HRUs) for management. The model is implemented by utilizing a digital elevation model, land use, soil type, and slope of the Genale basin; 464 HRUs were created, spreading over 25 sub-basins within the drainage area 54,942Km2. SUFI 2 algorithm of SWAT calibration & uncertainty programs (SWAT_CUP) is used to calibrate (1990 – 2005) and validated (2006 – 2013) streamflow & sediment on monthly scale, and the resulted statistics are; R2 = 0.87, 0.85 and NSE = 0.81, 0.78 for flow calibration and validation respectively whereas R2 = 0.84, 0.82 and NSE = 0.79, 0.75 for sediment calibration and validation respectively. Significant spatiotemporal variability of sediment yield was observed in the watershed, as the characteristics of the terrain, land use, & soil type in each sub-basin varies. Among the total 25 sub-basins, three sub-basins produced a very high sediment rate (21–31 ton/ha/year), one produced high (16–20 ton/ha/year), one is moderate (11–15 ton/ha/year), three were low (6–10 ton/ha/year), and the rest 16 sub-basins were under very low categories. In the case of SDR, three sub-basins have very high SDR (>0.452), two sub-basins resulted in high SDR (0.326–0.451), which are located at the upland basin. Based on the model results, sub-basins 6, 8, 12, 10, and 7 were identified as sediment-prone areas. Further investigation at the HRUs scale is taken to understand critical erosion areas and minimize the cost of management practice, time & human resources. HRU analysis has revealed the immense scope of minimizing cost by concentrating management measures only in the critical HRUs. For example, Sub-basin-6 has 31 HRUs, of which only seven are assessed to have the high rates of sediment yield and thus prioritized as; HRU-159, HRU-160, HRU-161, HRU-168, HRU-170, and HRU-171, which are located on agricultural and arable lands of steep slopes. [ABSTRACT FROM AUTHOR]

This paper identifies factors affecting perception of soil erosion, investment in soil and water conservation (SWC) on private plots and communal lands, and then preferences of grazing practices influencing watershed management. Using data from a survey of randomly selected 332 households, we employed different econometric tools (ordered probit , binary logit, multinomial logit and bivariate probit) as well as qualitative methods. Results of the ordered probit indicate that provision of training, perception on slope of the plot cultivated, holding of land certification are more likely to influence perception on severity of erosion. The multinomial logit shows different variables affecting the likelihood of practicing a specific SWC measure. Similar set of variables were also used to test their effect on the likelihood of adopting SWC measures on communal land and choice of grazing practices (communal and private). Moreover, coordination failure, and absence of land use plans and policy contributed to poor performance of watershed across the basin. These suggest the need to establish institutional mechanisms to mobilize the youth, introducing an integrated approach, sustained monitoring and evaluation of achievements. • Perceived soil erosion triggers investment in soil and water conservation. • Perceived and observed yield reduction do not prompt investment. • Better educated households prefer terracing and combine other measures. • Receiving advisory service on conservation measures motivates participation. • Poor performance of the watershed management is attributed to coordination failure. [ABSTRACT FROM AUTHOR]

Volcanic highlands supply water to 40% of the world's population. Soil degradation threatens this water supply. Studies on geohydrology that affect the effectiveness of land and water management (LWM) practices in reducing soil degradations are limited. To aid in the effectiveness of LWM practices, we conducted a field experiment in the Gomit watershed in the semihumid Ethiopian Highlands on the interaction of hydrogeology and LWM practices. We found that in a watershed with strongly faulted tertiary basalt, 30% of the rainfall was drained through faults to another basin. Consequently, the discharge at the outlet was less than half of that of other watersheds with quaternary basalts. Despite the high sediment concentration, i.e., around 15 g L−1, in the Gomit watershed, the sediment yield of less than 4 Mg ha−1 a−1 was below average for the agricultural watershed in Ethiopia because of the low runoff response. While some faults facilitated drainage, others acted as a barrier. Groundwater stored behind the barriers was used as a municipal potable water source. Since the effectiveness of LWM practices depends on the amount of erosion that can be prevented, considerations of country-wide prioritizing of investments in land and water management practices should include the geology of the watersheds. [ABSTRACT FROM AUTHOR]

• Trends and drivers of LULC changes were examined from 1973 to 2018 in Lake Ziway watershed of Ethiopia. • Cultivation, agroforestry, and human settlement LULC types are expanding in the watershed. • In the last 45 years, woodlands declined by 76% while cultivation and agroforestry increased by 45% and 11%, respectively. • Technical training should be established for local communities to mitigate the impacts of LULC changes. Assessing land use and land cover (LULC) change in Lake Ziway watershed is important to evaluate the degradation of ecosystems and their environmental processes caused by the ongoing increase in human pressures. The present study analyzed the long-term LULC dynamics in the Lake Ziway watershed, which covers 7300 km2 in the Ethiopian Central Rift Valley region. Three Landsat Satellite Image Series - Landsat MSS (1973), Landsat TM (1989) and Landsat Enhanced ETM+ (2018) - were the main input data from which three LULC maps were produced by employing Remote Sensing Techniques and Geographical Information Systems. The satellite data were supported by Google Earth and information gathered from informal discussions from local elderly people who are knowledgeable aboutthe area. The results over the last 45 years show that the major LULC changes in the study watershed have been the expansion of cultivated, agroforestry and settlement areas and the corresponding reduction in woodlands. Cultivation, agroforestry, and settlement LULC categories increased by 45%, 10.9%, and 141.4%, respectively. These changes are attributable to a combination of the ever increasing human population and the subsequent demands on environmental resources like agricultural lands, commercial and domestic fuelwood and charcoal. Other factors include poorly defined ownership arrangements and weak enforcement strategies on the existing land use policy. This has created open access mentalities among communities and intensified LULC changes in the watershed. Awareness raising and provision of technical training about conservation interventions should be provided to communities in the watershed.This study provides information for corrective measures to protect further degradation and irreversible losses that might happen to the biotic and abiotic resources in Lake Ziway watershed. [ABSTRACT FROM AUTHOR]