GIS-based identification of potential watershed recharge zones using analytic hierarchy process in Sikkim Himalayan region

Identification of groundwater recharge zone is an important factor for water resource management in any area. The present study investigates the potential water recharge zones in the Sikkim state, a mountain region of the Eastern Himalayas. To identify potential watershed recharge zone in the region, a combination of geographic information system (GIS)-based weighted overlay index (WOI) tools and analytic hierarchy process (AHP) pairwise matrix techniques was applied. The delineated watershed recharge sites were classified into five different potential zones. The results show that the majority of the study area (54.22%) was under moderate recharge potential zone. Some of the suitable recharge potential sites are forest-covered regions; therefore, the construction of surface check dams could be a suitable recharge method; it will escalate the discharge in springs and also help to make them perineal. This study provides first-hand information on the groundwater recharge potential of East Sikkim, where the populace depends largely on spring water discharge. Also, it is useful in selecting areas for digging staggered contour trenches, pits, and other structures to recharge the spring water and improve the watershed management system.