Identifying potential sites and structures for artificial groundwater recharge using GIS and AHP techniques: A case study of Erbil basin, Iraq
Excessive extraction and unregulated practices have caused severe depletion of groundwater resources in the Erbil basin. This has created a series of negative consequences on human habitation, agricultural activities, and the surrounding environment. Runoff harvesting and artificial groundwater recharge play a significant role in the sustainable management of water resources, particularly in arid and semi-arid regions. The present paper aims to: (1) delineate groundwater recharge zones using multiple thematic layers that control the groundwater recharge process, and (2) identify prospective sites and structures for artificial groundwater recharge. In order to generate a potential map for groundwater recharge zones, seven thematic layers are considered in this study, namely, topographic position index, geomorphology, lithology, land cover, slope, drainage-length density, and lineament-length density. After that, the analytic hierarchy process was applied to weight, rank, and reclassify these seven thematic layers. All maps are then integrated within the ArcGIS environment for delineating groundwater recharge zones. Accordingly, the resulting map categorizes the study area into five zones: extremely high, high, moderate, low, and extremely low potential for groundwater recharge. As expected, areas along the Greater Zab river show the highest possibility for groundwater recharge. Likewise, rugged eastern hills demonstrate an encouraging capacity for artificial aquifer recharge, whereas the least effective area is represented by built-up land. Based on the generated map, two dams are proposed as promising artificial recharge structures east of Erbil city. These results provide crucial evidence for implementing a sustainable management plan of surface and groundwater resources. The applied method is eventually valid for regions where appropriate and adequate field data availability is a serious issue.