Chapter 6 - GIS-based groundwater recharge potentiality analysis using frequency ratio and weights of evidence models

Abstract

Groundwater recharge in semiarid areas is difficult because of inadequate water sources and growing human demand. Henceforth, proper knowledge of aquifer recharge is essential for the management of groundwater resources. The prime aim of this study is to assess the groundwater recharge potential zone (GRPZ) using two statistical methods, that is, frequency ratio (FR) and weights of evidence (WOE), and geospatial techniques in the Jhargram district. This region is the drier region of Eastern India, and it has considered a low groundwater recharge potential area compared to plain land. For this purpose, we incorporate eight conditioning factors: elevation, slope, drainage density, lineament density, distance from the river, geomorphology, lithology, and land use/land cover using remote sensing data in ArcGIS software. All these conditioning factors have been reclassified, normalized, and processed in ArcGIS using the FR and WOE statistical methods. Then, the groundwater potential index has been formulated, and finally, GRPZ maps are generated based on selected two models. The result shows that a very high area of GRPZ is covered 26.06% and 24.55% under FR and WOE models, respectively. The receiver operating characteristic validation curves show that the FR method (AUC = 84.4%) is well obtained for GRPZ in comparison to the WOE (AUC = 82.5%) method. Therefore, this statistical method is highly recommended for the study of groundwater recharge potentiality assessment in drier regions like the Jhargram district. The outcome is very suitable for groundwater resources management in future land use planning. Precautionary works in low recharge potential areas should give priority to long-term planning. Thus, this study can be considered a good document for decision support in water exploitation planning and sustainable groundwater management in semiarid regions like Jhargram.