Abstact

RAINFALL RUNOFF MODELLING OF UNGAUGED CATCHMENT USING RS AND GIS

The rainfall and runoff relationship becomes an intriguing issue as urbanization continues to evolve worldwide. In this paper, we developed a simulation model based on the Soil Conservation Service Curve Number (SCSCN) method to analyse the rainfall-runoff relationship in Theni, Andipatti watershed. Remote sensing and GIS techniques are being increasingly used for planning, management and development of natural resources. The SCS-CN method was initially developed by the Natural Resources Conservation Service (NRCS) of the United States Department of Agriculture (USDA), and is one of the most enduring methods for estimating direct runoff volume in ungauged catchments. In the present study, Andipatti watershed was taken as case study for highlighting the role of GIS and RS in estimation of runoff from the watershed by SCS curve number method using OVERLAY techniques. The thematic layers such as land use/land cover and soil maps were derived from remotely sensed data and overlayed through ArcGIS software to assign the curve number on polygon wise. The runoff estimated from the SCS-CN model was then used to know the variation of runoff potential with different land use/land cover and with different soil conditions. Index Terms -- Rainfall-Runoff, Soil Conservation Service Curve Number (SCS-CN), Remote Sensing, GIS.