Identification of groundwater recharge site using geographical information system and remote sensing: case study of Sude district, Oromia, Ethiopia

Periodically, drought conditions due to rainfall variations in the Sude district cause water shortage problems during the dry period. Thus, scarcity and inaccessibility of the surface water resources cause inhabitants to exploit groundwater for their domestic uses and for cattle’s. Hence, proper information on the groundwater recharge site in this study area is fundamental for the proper management and use of groundwater resources. With this in mind, the current study was undertaken to delineate groundwater recharge sites in the Sude district using a remote sensing and geographic information systems approach via AHP. Thematic maps governing the existence of groundwater recharge sites such as slope, soil, land use/land cover, geology, lineament density, rainfall, runoff depth, and drainage density were used. The weights of these parameters were determined through the AHP method, and the groundwater recharge index was delineated by a weighted linear combination in Arc GIS 10.1 software. Finally, the groundwater recharge index was reclassified into four categories: very low, low, moderate, and high. The high class of groundwater recharge sites is only 1.49% and low groundwater sites constitute 76.2% of the study area. Hence, this district has low groundwater recharge potential for extraction. Finally, the delineated groundwater recharge map was validated by existing bore wells and hand-dug wells. From the study, it was concluded that delineation of groundwater recharge sites is helpful for effective recognition of suitable locations for groundwater extraction.