RUNOFF ESTIMATION OF MINI WATERSHED OF PEDDA KEDARI RESERVE FOREST, TEKKALI, SRIKAKULAM, AP USING REMOTE SENSING, GIS AND SCS CURVE NUMBER TECHNIQUES

The primary source of water is rainfall for the generation of runoff over the land surface. Runoff or overland flow is the flow of water that occurs when excess storm water flows over the earth's surface. Satellite remote sensing and GIS techniques coupled with conventional filed investigations were used for mapping of land use/land cover (LU/LC) features of the Mini Watershed of Pedda Kedari reserve forest towards estimating the runoff of the Mini watershed. The SCS-CN method (SCS, 1985) method involves the use of a simple empirical formula and readily available tables and curves. Determination of SCS curve number depends on the soil and land cover conditions, which the model represents as hydrologic soil group, cover type, treatment and hydrologic condition. Soils are classified into hydrologic soil groups (HSG) to indicate the minimum rate of infiltration obtained for bare soil after prolonged wetting. Runoff computed from a given rainfall event was integrated with the data of land use treatment, curve numbers and hydrological soil groups by using SCS-CN method. The estimated runoff contributes more than 37% of total rainfall received in the study area. The suitable locations of rainwater harvesting and artificial recharge structures are suggested to increase the groundwater levels for sustainable development of water resources in the Mini watershed of Pedda Kedari Reserve Forest