An assessment of potential infiltration areas to support groundwater supply system in Jagakarsa, South Jakarta, based on Multi-Criteria Decision-Making (MCDM) analysis

Jagakarsa is an urban area in South Jakarta, Indonesia, that uses groundwater for raw water because there are no clean water supply facilities. The significant increase in the need for clean water due to increasing urbanization threatens groundwater availability to maintain the balance of the surrounding environment. Natural conditions with a deep layer of clay and a dense built environment further increase runoff capacity because water has difficulty seeping into the soil. The intense extraction of groundwater without balancing groundwater recharge results in land subsidence. Until now, there has been no research on this issue. Thus, our research is necessary. This research aims to assess the potential of groundwater infiltration areas in Jagakarsa. Due to limited data, as a first step, we used a qualitative model with MCDM analysis (AHP and MIF methods) integrated with GIS to map potential groundwater recharge areas. The AHP method is explained in detail with a matrix system formula, readers can understand the calculation steps more easily. This study uses five influencing factors: geological formation, land use, slope, rainfall, and soil type. The results show that most study locations have low potential (AHP 74.49 % and MIF 75.25 %) for groundwater recharge. This groundwater recharge potential map was validated using groundwater level measurements. The accuracy of the AHP is 74.51 %, and the MIF method reaches 75.26 %. Therefore, further research is needed to obtain appropriate and effective technology for maintaining groundwater availability.