Spatial runoff estimation and mapping of potential water harvesting sites using GIS and Remote Sensing

The worsening of drought conditions has significantly increased water scarcity, notably impacting arid and semiarid regions globally. Consequently, effective runoff management has emerged as a critical challenge. Different maps were overlaid to identify appropriate locations for water harvesting structures, considering technical and social factors such as soil texture, slope gradient, land use/cover (LULC) and flow accumulation. Applications of remote sensing and GIS (Geographic Information System) were integrated to accomplish this goal. Designing water harvesting structures requires an accurate understanding of runoff from rainfall. Although direct field-level runoff assessment is beneficial, it is costly, time-consuming and laborintensive. The precipitation data for runoff calculations were obtained from an automatic weather station installed within the study area, while soil and land use/cover data were sourced from the Rejuvenating Watersheds for Agricultural Resilience through Innovative Development (REWARD) project. The modified infiltration approach was utilized to store, analyze and estimate runoff depth, surface storage and runoff volume utilizing the GIS tools. The runoff volume for harvesting in 2019 was 0.62 MCM (Million cubic meters) and that in 2021 was 1.09 MCM. The suitable sites in the study area were identified 24.50% as suitable for contour bunds, 4.0% for staggered trenches, 5.14% for V-shaped ditches and 8.35% for continuous trenches. Additionally, water harvesting structures were proposed for the Integrated Mission for Sustainable Development (IMSD) guidelines, with 40.20% of the structures deemed suitable for farm ponds, 8.70% for check dams and 8.35% for percolation ponds.