Irrigation practices causing vulnerability of groundwater resources in water scarce Goghat-Ⅰ and Ⅱ Blocks of Hugli District using MCDA, AHP, Fuzzy logic and novel ensemble models

摘要

This study tries to show the vulnerability of dynamic groundwater resources in water scarce Goghat-Ⅰ and Ⅱ blocks of West Bengal. Central Ground Water Board (CGWB) of India has classified Goghat-Ⅰ as a semi-critical and Goghat-Ⅱ as the only critical block of West Bengal. Abstraction rate of annual rechargeable groundwater is a matter of concern in these blocks. Different methods like MCDA, AHP, Fuzzy logic and ensemble has been used to find out the spatial vulnerability of renewable groundwater resources. Annual ground-water recharge has been measured by the WLF method, whereas abstraction for irrigation and domestic use has been measured through field survey. These are essential to show the use of the water resource, which reveals the level of vulnerability of this precious natural and dynamic resource. In both the blocks, over 80% of renewable resource is used; and the trend of groundwater level is continuously decreasing over the years. Sustainability of groundwater is a concern for both the blocks. Various controlling factors of groundwater vulnerability have been used to show the micro-level variation of vulnerability over this region. Results of all the methods reveal that very low and low vulnerability is present in north-eastern and southern parts in small extent. High and very high vulnerability is found in the entire western, north-western and south-eastern parts; and it is present over an extensive area. Rest of the area represents moderate vulnerable areas. ROC curve is used to validate the results; AUC value of more than 0.8 for all the methods shows that the applied methods are suitable for this study.