Rainfall- Runoff Modelling Using SCS-CN Method: A Case Study of Krishnagiri District, Tamilnadu

Runoff is one of the most important hydrological variables used in most of the land and water resources applications. The determination of surface runoff at micro level is essential to address soil and water conservation practices in a watershed. Understanding the basic relationships between rainfall, runoff and soil loss are studied for effective management and utilization of water resources and soil conservation service. Curve Number (CN) method is mainly used for estimating infiltration characteristics of the watershed, based on the land use property and soil property. In the present study an attempt is made to estimate the surface runoff for Krishnagiri district, Tamil Nadu using SCS- CN method. Hydrological soil group (HSG), land use / land cover Map, Soil and multi spectral remote sensing data are used for the analysis. Runoff is computed for different areas barren land, agriculture, industrial, forest. Based on these derived information soil classification falls under group C. The estimated amount of average annual surface runoff is 76.53 mm, which is corresponds to 54 % of annual average rainfall of Krishnagiri district. These details is useful to identifying runoff potential in Krishnagiri district and developing appropriate soil and water conservation structures.