Estimation of rainfall–runoff using SCS-CN method and GIS techniques in drought-prone area of Upper Kangsabati Watershed, India

Purulia is one of the most intense drought-prone districts of the western part of West Bengal, India. Acute form of water scarcity is a common phenomenon in this area during the hot-summer period. The water scarcity in this study region is due to the presence of monsoonal vagaries, unfavorable lithological condition and availability of poor groundwater. Therefore, watershed management is the primary concern for sustainable development of natural resources like water and land for optimal development of watershed and economic activities. Therefore, optimal measurement of rainfall-induced runoff is indeed necessary to understand the hydrological behavior. Several traditional statistical and advanced machine learning methods has been used previously to measure surface runoff among the researchers. It is difficult to simulate the required runoff with physical-based models due to the complexity and non-linear behavior of the runoff phenomena, as well as the absence of relevant historical data in all places. Thus, in the present research study of gravelly dominated drought-prone area of Upper Kangsabati Watershed (UKW) is considered to assess rainfall-induced surface runoff using most reliable method of Soil Conservation Service Curve Number (SCS-CN), and considering remote sensing and geographic information system platform. The SCS-CN method is very much reliable and till now has been frequently used among the global hydrological community to optimal assessment of surface runoff and adaptation of proper watershed management strategies. Henceforth, in this study SSC-CN method is used in the hard rock terrain landscape of extended plateau fringe of western West Bengal. The estimated result of runoff depth and runoff volume is 979.45 mm and 280.85 m³, respectively, and the rainfall–runoff is strongly positively correlated with (r) value being 0.98. Additionally, the applied statistical methods and the outcomes of this study will be helpful among the hydrological communities, different stakeholders and policy makers for sustainable watershed management in terms of optimal conserve of water resources and reduced threating of drought condition.