An Approach to Delineate Potential Groundwater Zones in Kilinochchi District, Sri Lanka, Using GIS Techniques

Abstract

The scarcity of surface water resources in the dry season in the Kilinochchi district increases the demand for freshwater. Therefore, the main objective of this study is to delineate potential groundwater zones in Kilinochchi, Sri Lanka, using integrated remote sensing (RS), geographic information systems (GIS) and the analytical hierarchy process (AHP). Groundwater potential zones are demarcated for the Kilinochchi district by overlaying thematic layers: geology, geomorphology, land use/land cover, soil types, drainage density, slope, lineament, and rainfall. The thematic layers were integrated into a geographic information system, and a weighted overlay analysis was carried out to delineate groundwater zones. Thus the resultant map is categorized into five different potential zones: very low (59.12 km2), low (207.78 km2), moderate (309.89 km2), high (507.74 km2), and very high (111.26 km2). The groundwater potential map was validated with the existing seventy-nine wells, which indicated a good prediction accuracy of 81.8%. This suggests that the results obtained by integrating RS-GIS and AHP are well-matched with the existing well water depth. The AHP approach based on RS-GIS was a handy and efficient technique for assessing potential groundwater zones. This research will help policymakers better manage the Kilinochchi district’s groundwater resources and give scope for further research into groundwater exploration in the area.

Identification of Groundwater Potential Zones (GWPZ) Using Geospatial Techniques and AHP Method: a Case Study of the Boudinar Basin, Rif Belt (Morocco)

“…The validation of results is an essential step in any predictive modeling in order to have scientific significance [25,26,45]. For the validation of GWPZ, various methods have been widely used, such as receiver performance analysis (ROC), and curve area (AUC) [9,18,23,37].…”

“…High-degree slopes increase the runoff and decrease the infiltration (lower weights), whereas the low-degree slope and flat surface facilitate groundwater recharge (higher weights) (Tab. 6) [26]. The slope gradients in the Boudinar Basin (Fig.…”

“…It is worth indicating that the consistency ratio (CR) should be less than 0.1 to consider the weights affected logically by the factors. The authors used the same parameter Elevation (altitude) [35], [38], [39] Soil [39], [40], [41] Distance from fault [3] Distance from river [3] Drainage density [9], [33], [41] Lineament density [23], [27], [40] Lithology [33], [35], [39] LULC [23], [26], [33] NDVI [3], [14], [33] Profile curvature [3]…”

“…The slope of an area is an essential parameter in identifying GWPZ [10, 23,26], it determines the rate of infiltration and runoff of surface water [10,38]. High-degree slopes increase the runoff and decrease the infiltration (lower weights), whereas the low-degree slope and flat surface facilitate groundwater recharge (higher weights) (Tab.…”

“…Both NDVI and LULC were equally important in GWPZ delineation, as they provide essential information on infiltration [26]. The NDVI (Fig.…”