Mapping of groundwater potential zones in hard rock terrain using geoinformatics: a case of Kumari watershed in western part of West Bengal

Abstract

Groundwater is one of the world’s most precious natural resources. But still now this valuable resource is largely unexploited for agricultural development in drought prone western region of West Bengal. In drought prone areas micro-watershed based development strategy may be considered as the best practice for integrated development. Keeping in view the above perspective, we select Kumari watershed of Purulia district, the westernmost and semi-arid district of West Bengal for better water resource management. Geologically the area consists of Chotanagpur granite gneiss complex while physiographically it is highly dissected pedimental landscape with lateritic upland and skeletal soil. As a result, cultivation of this area is predominantly mono-cropped and thus per hectare production is also low as compared to other regions of West Bengal. Supply of sufficient water resource in this region may offer more food security alternative to rain-fed subsistence farming. That’s why the present study has been carried out to evaluate the potential zones for groundwater targeting in Kumari watershed of Purulia district using an integrated remote sensing data, Survey of India topographical sheets and field verification. Hydro-geological features (geomorphological and geological units, slope, drainage density, lineaments density etc.) that influence groundwater occurrence were extracted and integrated to evaluate the hydro-geomorphological characteristics of the study area. Thematic maps of the extracted features were prepared with the help of ERDAS Imagine 9.0 and Arc-GIS 9.3 software. Weightage values were assigned to the different parameters according to their relative importance to groundwater potentiality and integrated through Geographic Information System environment. Finally on the basis of grid-wise theme weight and class weights the groundwater potential map was prepared by overlay the thematic layers.