Assessment of groundwater potential zones in Chittar basin, Southern India using GIS based AHP technique

The present study investigates multiple geo-envrionmental parameters for delineating groundwater potential zones in Chittar basin, Tamil Nadu using GIS based analytical hierarchical process (AHP) technique. The parameters contributing groundwater recharge and sub-surface flow such as geology, lineaments, geomorphology, slope, drainage density, soil and rainfall are spatially explored at site-specific level based on the expert guidelines of AHP systematic weighted analysis. In this analysis, each thematic layer of contributing parameter is mathematically calculated for normalized weights and geometric mean in order to determine its rule to identify potential groundwater prospects at pixel (10 × 10 m) scale level. The result map indicates the potentiality of groundwater availability in various parts of the study area. In which, the area covers 162.84 km2 (6.6%) are identified with higher groundwater prospectus, that occurs under confined aquifers lay down along the flow path of river channel; whereas the poor groundwater potential found in the area of 180.52 km2 (7.37%) in the western parts due to leaking or discharge from unconfined aquifers towards east-down directions. The result is validated using field-estimated groundwater optimum yield for the 24 open wells located across the study area and the among them 17 wells are highly correlated with the derived measurements, i.e. the higher groundwater potential in Keelapavoor in south-west parts and poor groundwater availability in Devarkulam and surrounded areas and the overall accuracy is agreed at 71%. Higher groundwater potential found along some parts due to presence of lineaments occurred in weathered and jointed rocks that transmitting surface runoff into the confined aquifers; however, zones covered by massive weathered rocky layers prevails poor groundwater sources in many parts of the study area. The GIS based AHP method is effectively performed for identification of groundwater potential zone in the hard rock terrain and the information sources can be used for planning the sustainable groundwater management. Groundwater potential zones of the study area. [Display omitted] •Eight influencing factors have been selected and analyzed using AHP technique.•The eight selected parameters and their feature classes were assigned suitable weights.•The groundwater potential zones of Chittar basin were delineated and classified.•The validation of results performed by comparing with the optimum yield data.