Study on the water resources and feasibility of rainwater harvesting for agricultural purposes in Kumari river basin West Bengal and Jharkhand India

Abstract

Kumari basin is a sub-basin of Kangsabati basin with a total area of 1976.15 km2. The main objectives of the study are groundwater and irrigational water pattern availability assessment, analysis of spatiotemporal distribution of hydrological budget components of the region, and finally and most importantly identifying and suggesting suitable rainwater harvesting sites and structures. newlineThe groundwater level of the study has been measured by temporal field surveys. Soil and water assessment tool (SWAT) model has been applied for water budget estimation. Geographic Information System (GIS) based Analytic Hierarchy Process (AHP) model has been used for surface rainwater harvesting suitability assessment. newlineFrom the spatiotemporal study of the groundwater level of the basin, it can be seen that in the monsoons, the water level varies from 1-6 mbgl, the water level in the pre-monsoon season is 3-13 mbgl and in the post-monsoon season, the water level ranges from 1-9 mbgl. newlineWhile understanding the distribution of the hydrological budget components of the basin it is observed that the annual precipitation amount of the basin is 2183.8 mm whereas its annual surface and subsurface lateral flow are 809.55 mm and 8.42 mm respectively which is nearly 37.36% of the net precipitation. To estimate the rainwater harvesting suitability sites in the Kumari basin, 12 factors are taken into consideration. The suitability map is classified into 4 classes of which 20.26% show high suitability zones, 32.74% are moderately suitable zones, 29.40% are less suitable zones and 17.60% are unsuitable zones. The predictive accuracy of the model is 87.4%, which indicates an excellent accuracy rate. newline