A Study on Surface Water - Groundwater Interaction in the Jaffna Peninsula, Sri Lanka

Groundwater depletion during the low rainfall period and flash floods during the monsoonal period are the predominant issues identified in the Jaffna Peninsula, the Northern part of Sri Lanka. The managed artificial recharge of groundwater aquifers using excess runoff is considered a feasible solution. Analytical Hierarchy Process (AHP) analysis was initially performed to develop an Artificial Groundwater Recharging Potential Zone Mapping (GWPZM) based on seven different groundwater behavioural influencing factors. A water resource action plan was developed to propose suitable stormwater quality and quantity controlling structures according to the unique hydrogeological behaviour of the Jaffna Peninsula. The proposed major artificial recharging units were introduced in the areas with adequate groundwater infiltration potential sites. Recharging reservoirs were assigned for the lagoon region with silt sedimentation. Dry wells were proposed for the region adjacent to the floodplain along with stormwater quality control structures. Paleochannel footprints were not found in the preliminary studies. Flood analysis using Rainfall-Runoff-Inundation (RRI) Model indicated that the simulated inundation area of the 2017 flood event is reduced by 41.47% after the establishment of artificial recharging techniques. A fundamental idea of Web GIS was suggested for real-time monitoring purposes.