Identification of artificial groundwater recharge zones in semi-arid region of southern India using geospatial and integrated decision-making approaches
M. Rajasekhar, K Ajaykumar, Sudarsana Raju G., Vijay Bhagat
Abstract
The present study integrates various decision-making methods viz. Fuzzy Logic (FL), Frequency Ratio (FR), Analytical Hierarchy Process (AHP) to delineate the artificial groundwater recharge zones (AGRZs) in semi-arid region of south India. Eight criterions used in this process, including lithology, soil types, lineament density (LD), drainage density (DD), vadose zone (VZ), rainfall, land use/ land cover (LULC), and slope. All of these criteria and their sub-criteria used to derive weights for different thematic layers and combined using a geospatial method to classify AGRZs. The resultant map was categorised into five classes: very poor, poor, moderate, good and very good. The FL, AHP, FR, and integrated approaches were validated against groundwater fluctuation data using receiver operating characteristic (ROC) and field AUC [Area Under the Curve] approaches, showed an accuracy of 72%, 76% and 78% and 82%. As a result, the output of the integrated models outperforms that of the FR, FL and AHP models. Fuzzy reasoning and AHP methods rely on assigning a relative score based on the significance of the variables, which necessitates extensive knowledge of the criterions. FR, on the other hand, is simpler and more reliable since it does not rely on user-based scoring for the various criterions. The results of this study can be useful for decision makers responsible for the sustainable management of groundwater resources.