Village-Level Assessment of Potential Surface Water Storage Using an Integrated Water Balance Approach in the Ippala Vagu Watershed, India

Abstract

The management of watersheds requires the planning of surface water resources. For hydrological analysis, runoff estimation is essential. This study aimed to estimate the village-level potential surface water storage by integrating the water balance components, including surface runoff, groundwater recharge, and effective rainfall. Surface runoff was estimated using the Soil Conservation Service Curve Number (SCS-CN), groundwater recharge was estimated by the Rainfall Infiltration Factor (RIF), and effective rainfall was estimated by Food and Agriculture Organization/ Agricultural Water Management Group (FAO/AGLW) approaches. Using rainfall data, water balance calculations were performed for the 18 villages within the Ippala Vagu Watershed to evaluate potential surface water storage. In total, 18 villages recorded an annual rainfall volume of 430.50 million cubic meters (MCM), of which 138.24 MCM (32.11%) was estimated as effective rainfall. Surface runoff constituted 71.57 MCM (16.62%), while groundwater recharge was estimated at 68.88 MCM (16.00%). The potential surface water storage amounted to 151.82 MCM, representing 35.27% of the annual precipitation volume. The current storage capacity was merely 73.67 MCM, constituting 48.52% of the potential surface water storage. These findings indicate considerable potential for improving the utilization of available surface water resources within the watershed. Accordingly, increasing water harvesting and storage facilities, especially in villages with high potential surface water storage, is recommended.