Identification of Potential Artificial Groundwater Recharge Zones in Tikurwuha Watershed of Ethiopia

Abstract

Abstract Groundwater extraction has increased alarmingly in association with urbanization and population growth to fulfill the high water demand worldwide. On the other hand, urbanization cause reduction of the natural groundwater recharge due to deforestation and increase in impervious area. This problem is also common in most parts of Ethiopia including the study area. This study thus attempts to identify the potential artificial groundwater recharge zones in Tikurwuha watershed for implementation of artificial groundwater recharge techniques. To do this Geographic information system based multi criteria decision making method was used. Nine factors selected in the analysis process include rainfall, soil texture, geology, normalized difference vegetation index (as land use land cover indicator), slope, topographic position index, topographic wetness index, drainage density and lineament density. These factors were generated using study area rainfall, soil texture, geology, Landsat image and digital elevation model. The relative importance between pair of factors was decided using local expert interview and review of similar studies. The factors weights were then derived using analytical hierarchy process using decided relative importance. Weighted overlay was finally performed after Suitability classes have generated for each factor based on standards or expert interview. The final potential artificial groundwater recharge zones suitability class showed an area of extremely high (0.5625 hectare (0.001%)), high (20003.7 hectare (30.959%)), moderate (42428.17 hectare (65.665%)), poor (2179.656 hectare (3.373%)) and very poor (1.312 hectare (0.002%)). As extremely high potential sites are insignificant decision makers can use high potential sites for the implementation of artificial groundwater recharge techniques.