Estimation of runoff potential and planning of water harvesting structures using geospatial techniques for halia basin

Runoff is one of most important hydrological component that is used in planning for rainwater harvesting structures, groundwater recharge structures, optimal use of reservoirs and warning of flood hazards. Adoption of in-situ soil and water conservation techniques and construction of rainwater harvesting structures are very essential for moisture conservation and rainwater harvesting for supplemental irrigation especially in cases of unpredictable nature of monsoon rainfall. Planning and implementation of rainwater harvesting structures like farm ponds, check dams, percolation tanks etc. needs data of runoff potential for its long-term sustainability. The present study was taken up in Halia river basin located in Nalgonda district of Telangana where the runoff data availability is very limited. Hence, SCS-CN and GIS was used for estimating the runoff potential availability over the years. The Halia basin was delineated using ARC Hydro tool and 416 sub-catchments were generated. The main soil types found in the basin are clay skeletal, clayey, loamy, and loamy skeletal. Different thematic layers were intercepted in ArcGIS and SCS-CN method was applied to estimate the runoff spatially. Most of the study area has rainfall less than 790 mm. Most of the catchment has runoff ranged from 10.5% to 17.5% of average annual rainfall. The potential sites for water harvesting structures like ponds, check dams and percolation tanks were identified using geospatial techniques. This layer was converted into. kml file format and exported to Google earth and locations of existing structures were validated in Google earth and by visual interpretations. The ground truth related to location of existing structures was collected during the survey and was exported to ArcGIS and identified new potential sites for planning of additional structures.