Institute of Technology

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The Institute of Technology focuses on education, research, and innovation in engineering, technology, and applied sciences to support sustainable development.

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    GIS-BASED SURFACE IRRIGATION POTENTIAL ASSESSMENT: A CASE STUDY IN MUGA WATERSHED EAST GOJAM ZONE, AMHARA REGION, ETHIOPIA
    (Hawassa University, 2021-10-22) ZELALEM ABEZA
    Assessing available water and land for surface irrigation is important for planning their use. The high dependency on rain-fed farming and erratic rainfall require alternative ways of improving agricultural production. The alternative to improve is through development of small scale irrigation schemes by assessing the available suitable land and water resources in sub-basin level. The objective of this study was assessing the land and water resources potential of Muga watershed in East Gojjam Zone for surface irrigation development using Geographic Information System. Identification of suitable land, estimation of available river flow, and determination of irrigation water requirement were the main steps that were followed. The land irrigation suitability factors considered were: slope, soil, land use/land cover, and river proximity. Estimation of river flow in the six manually added outlets was conducted by simulation after calibration and validation were carried out with the observed flow of gauged river using Soil and water assessment tool. The commonly cultivated crops in the area maize, onion and potato were selected, and the irrigation water requirements of these crops were determined using the CROPWAT8.0 model. Comparison between gross irrigation water requirement of the selected crops for the identified suitable land with simulated river flow at the area of the selected site was carried out. Overall, the weighted overlay analysis of these factors gave a suitable land among river sub-basin as G/muga 560ha, E/muga 3057ha, Bora 670ha, Gibstawit 404ha, and Genet 241ha. Mean monthly flow of 11.4m3 /s were determined at the watershed. A total of 3443ha (5.1%) was found to be potentially suitable for the development of surface irrigation project from a total watershed area of 67535ha. In conclusion, the irrigation potential of the area could be increased either by harvesting rainwater or using groundwater.
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    GIS-BASED SURFACE IRRIGATION POTENTIAL ASSESSMENT OF MEKI RIVER WATERSHED, CENTRAL RIFT VALLEY OF ETHIOPIA
    (Hawassa University, 2023-07-16) KUFA KAFU MILO
    Irrigation can contribute to food security by increasing food availability and cash income of smallholder farmers. However, surface irrigation development in the study area is hindered due to lack of reliable data of suitable land and available water potential. Therefore, this study assessed the land and water resources of Meki River watershed in rift valley lakes basin in Ethiopia using Geographic information system to identify suitable land and available water potential for surface irrigation. Land suitability factors such as soil depth, soil texture, soil drainage, slope and land use/cover were considered and their suitability analyzed using ArcGis10.3. Water availability assessed using soil and water assessment tool and calibrated and validated with observed flow. Flow duration curve from monthly simulated flow was developed to obtain the reliable monthly flow at 80% probability. Irrigation water requirements estimated using CROPWAT8.0 for the Maize, Onion and Tomato and compared with dependable flow to compute the potential irrigable area. Regarding evaluation factors the results showed that 52.31 % of slope, 89.9% % of soil depth, 75.95% of soil drainage 99.65% of soil texture and 94.73 % of land use land cover were in the range of highly to marginally suitable, whereas 47.69 % of slope, 10.1% of soil depth, 24.1% of soil drainage, 0.35% of soil texture and 5.27 % of land use land cover restricted for surface irrigation. Further weighted overlay results showed that 177,199 ha were in the range of highly to marginally suitable whereas 35798 ha were unsuitable. Besides, the results revealed that maximum and minimum dependable flow during crop growing period were 39.6 m 3 /s and 0.05 m 3 /s respectively. Moreover, the results showed that irrigation water demands vary from crop to crop, and 4126.04 ha were obtained to be potentially suitable for the development of surface irrigation project. This study concludes that there is huge suitable land and insufficient water availability in the watershed. Therefore, irrigation potential of the watershed can be increased through using water saving technology such as drip, sprinkler and selecting other less sensitive crops, also using other water sources such as Lake Water, ground water and rain water harvesting
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    ASSESSMENT OF SURFACE IRRIGATION POTENTIAL: THE CASE OF GIDABO WATERSHED, RIFT VALLEY LAKES BASIN, ETHIOPIA
    (Hawassa University, 2019-03-07) AZEMERAW ALEMU
    Ethiopia has immense potential in expanding irrigated agriculture. Irrigable land assessment is essential for the development of irrigated agriculture. The study was aimed at assessing land potential of Gidado watershed. Land suitable for irrigation development was determined with a GIS-based multi-criteria evaluation, which considers the interaction of various factors such as slope, soil, LULC, proximity to river and road. The Analytical Hierarchal Process (AHP) and ArcSWAT were used for analyzing the different factors by assigning weights and mapping of suitable potential irrigable areas and surface water potential of the study area was estimated using SWAT model respectively. The model was calibrated and validated from observed stream flow data at three monitoring sites within the watershed using the periods of 1993-2004 and 2005-2012 respectively by using SWAT-CUP program and Global Sensitivity Analysis (GSA) was used for identifying important model parameters. The irrigable land of the area was identified using weighted overlay analysis of the suitability parameters, thus the result indicated that 1138.31 km2 areas was classified suitable and 2042.19 km2 area was classified as not suitable for surface irrigation. During calibration and validation, the results of model performance indicators were in the acceptable range (R 2= 0.68, 0.73, 0.72), (NSE = 0.60, 0.63, 0.71) and (PBIAS=12.2, -9.0 and -14.0) for Gidabo, Kola and Bedessa rivers respectively which indicated that a good to very good agreement between observed and simulated values. And average surface water resource potential of the catchment estimated to be 86.36m3 /s or 223.86 MCM. However after analyzing 25 years river discharge and determined the water demand of the crop, 74390.89ha (23.39%) of the potential irrigable area was estimated and could be irrigated consistently with runoff from the river systems. For sustainable irrigation development, other suitability factors such as soil chemical properties, socio-economic, environmental issues, and distance from markets and town should be considered
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    GIS-BASED SURFACE IRRIGATION POTENTIAL ASSESSMENT: A CASE STUDY IN BILATE RIVER WATERSHED, SOUTH-WESTERN, ETHIOPIA
    (Hawassa University, 2021-04-26) ALELU MANAMO MERASA
    The major problem associated with rainfall-dependent agriculture in Ethiopia is the high degree of rainfall variability and unreliability. As a consequence, food insecurity often turns into famine. Irrigation development is one of the key strategies to increase agricultural production and alleviate poverty. This study, therefore, aimed to assess the surface irrigation potential and land resources potential of the Bilate River Watershed for irrigation expansion. Watershed delineation, identification of potentially irrigable land, and estimation of irrigation water requirement and surface water resources availability of the study area were the steps followed to evaluate this irrigation potential. Irrigation potential was mapped by using GIS of the watershed; Arc SWAT model was used to estimate the water resources availability in the watershed; Analytical hierarchy process (AHP) comparison was used to conduct land suitability assessment and a CROPWAT 8.0 model was used to determine the crop water requirement for major crops of the study area. To identify potentially irrigable land, irrigation suitability factors such as soil physical properties, slope, land use/ land cover, and distances from the water supply (sources) are taken into account. The final results of the overall weighted overlay analysis of irrigation land suitability indicate that 317,841ha (64%) are highly suitable (S1), 153,459ha (30.91%) are moderately suitable (S2), whereas 25,039ha (5.044%) are not suitable (N) for surface irrigation development. The SWAT model was calibrated and validated. The observed monthly streamflow values have a coefficient of determination (R2 ) and Nash-Sutcliffe Coefficient (NSE) of 0.77 and 0.66 respectively for the calibration period and 0.81 and 0.64 for the validation period. The irrigation water demand required by five major selected crops which are grown in the study area throughout the growing season was found to be 663.04 m 3 /s. The annual dependably simulated streamflow was 225.14 m 3 /s. The estimated dependably available flow can potentially irrigate only an area of 53,645.77 ha for highly suitable areas. The result showed that the water demand of the crops was greater than the available dependably flow of the watershed. Therefore to increase the irrigation potential of the watershed sprinkler or drip irrigation methods can be used