Assessment of groundwater vulnerability to over-exploitation using MCDA, AHP, fuzzy logic and novel ensemble models: a case study of Goghat-I and II blocks of West Bengal, India

The vulnerability of groundwater to over-exploitation has been assessed in Goghat-I and II blocks of West Bengal using a number of different methods, i.e., MCDA, AHP, fuzzy logic and ensemble method in a GIS environment. Annual groundwater recharge has been measured through the water level fluctuation method, whereas groundwater abstraction data have been obtained from field investigations. The results of the assessment indicate that much of the study area is highly vulnerable to groundwater level decline due to excessive groundwater use. Result of all the methods reveals that very low and low vulnerable zones are present in north-eastern and southern parts in small extent. Extensive areas in the entire western, north-western and south-eastern parts represent high and very high vulnerable zones. Results of all the methods have been validated using the ROC curve, which produce AUC values of more than 0.8 for all the models. It shows that the applied methods produce reliable results. The methodologies developed in this study could be used to assess groundwater vulnerability to over-exploitation in other water-stressed regions.