Water Resource
Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/71
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Item ASSESSMENT OF SURFACE IRRIGATION POTENTIAL: THE CASE OF GIDABO WATERSHED, RIFT VALLEY LAKES BASIN, ETHIOPIA(Hawassa University, 2019-03-07) AZEMERAW ALEMUEthiopia 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 consideredItem IDENTIFICATION OF GROUNDWATER POTENTIAL ZONE BY USING GIS AND REMOTESENSING IN SUTEN TO TORA SUB-CATCHMENT, RIFT VALLEY LAKES BASIN, SOUTHERN ETHIOPIA(Hawassa Unversity, 2019-10-21) ASCHALEW GURMUThis study was aimed to mapping of Groundwater potential investigation of Suten-Tora sub catchment in the Rift Valley Lakes basin, Southern Ethiopia. Climate, hydro-geological, land use/land cover, soil, lithology, geomorphology and stratigraphic data were collected, analyzed and inferred. The aquifer characteristics from the well completion reports were used to map the Groundwater flow direction. A Groundwater level contour map; which developed from well completion report is revealed that the Groundwater flows from western towards the center and eastern part of the sub-catchment. The results also inferred from the geological formations show that the Suten-Tora Sub-catchment are mainly covered by partially welded pyroclastic flow, Gash Megal rhyolitic lava flows, Guraghe-Anchor basalt, Nazret welded pyroclastic, Lacustrine sediment, Mesozoic sediment, porphyritic rhyolitic lava domes, Wonji basalts, Precambrian basement complex and recent basalt flows. Moreover, there is also a Geological structure in the study area. The linear feature of these structures are characterized by three distinct interconnected fault trends systems are called in NW-SE, NE-SW and N-S which are more or less affect the availability of Groundwater potential. Among the above listed lithological formations lacustrine sediments, Wonji basalt with scoria deposit and pyroclastic are coincide with high Groundwater potential zone. Similarly a moderate Groundwater potential zone is covered by Geological formations; e.g. Chefe Donsa, un-welded to poorly weld pyroclastic and others small formations. In the other way low and very low potential zones are covered by depositions of Nazret pyroclastic, Gash Megal rhyolite and other similar lithological formations. For the delineation of Groundwater potential zones, the weight over analysis of different factors namely: lineament density, lithology, geomorphology, slope, soil texture, drainage density, rainfall and elevation have been analyzed through the Analytical Hierarchal process (AHP) and ArcGIS 10.3 software. The delineated Groundwater potential zone was categories into four classes namely high, moderate, low and very low potential zone. These delineated Groundwater potential zones class called high, Moderate, Low and very low potential zones are covers an area of around 50%, 20%, 16% and 14% of the total sub catchment area respectively. To conclude that; the center and southeastern parts of the sub catchment have high amounts of Groundwater potential. However the western part has les Groundwater potential. Depend on the validation of output accuracy level; the delineation of Groundwater potential zones by using GIS and remote sensing techniques is important method. Finally it has been recommend that ; the well drillers in this study area suggested to use this Groundwater potential zone map as information