Modeling Approach for Identification of Potential Rainwater Harvesting Sites in Arsi Zone, Eastern Ethiopia.
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Date
2017-05
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Addis Ababa Universty
Abstract
Water plays a crucial role in fulfilling basic human needs, for socio-economic developments and for ecosystem services. Absence of this vital resource for extended periods, make severe drought in the affected areas. Ethiopia is currently experiencing growing pressure on water resources caused by increasing water demand mostly for agricultural and domestic uses. This has been brought due to the effects of climate change and country development in agro-industrialization sector. This study was conducted in Arsi Zone, which is located in eastern Ethiopia. Arsi Zone frequently faces drought, crop failure and lack of permanent sources of water. Rain Water Harvesting (RWH) has been considered as the most encouraging among others with endeavors, to provide water to meet the increasing necessity. The objective of this study is to develop a model for the identification of potential RWH sites in Arsi Zone, Eastern Ethiopia, integrating Multi Criteria Decision Analysis (MCDA), which uses Analytical Hierarchy Processes (AHP) with a Fuzzy logic approach and Geographical Information System (GIS). Eleven physical characteristics of the study area layers were adopted for the analysis. The soil conservation service (SCS) model was used to estimate the runoff depth layer of the study area. Weighting was made based on environmental, socio-economical and hydro-geological characteristics of the study area, and reviewed literature. Fuzzification and Weighted Linear Combination (WLC) aggregation was made in order to get the result. In addition to aggregation, the analysis used Boolean Intersection of MCDA methodology to identify and exclude restricted environmental and geological constraints. The result of this research shows that, each potential suitability class coverage was: not suitable 5769.8 km2 (27.88%), less suitable 3104.34 km2 (15%), suitable 5695.42 km2 (27.52%), very suitable 4097 km2 (19.8%) and extremely suitable 2027.38 km2 (9.8%). The area coverage of constraints were 4,540.37 km2 (21.94%) of study area. The outcome of this study emphasized the importance of geospatial modeling in assessing RWH potential sites, proposed to assist in planning water facility and to address the water scarcity problem in Arsi Zone. In addition, the model developed in this research can be used in other areas to determine the potential of RWH and integrate rainwater as an alternative water source to ensure sustainable development. Detail ground validation and survey; using high-resolution data in modeling and study on environmental impact assessment before implementation are among the recommendations.
Keywords: Arsi Zone, RWH, Fuzzy logic, MCDA, Boolean Intersection, AHP, FAHP, WLC
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Keywords
Arsi Zone, RWH, Fuzzy logic, MCDA, Boolean Intersection, AHP, FAHP, WLC