Modelling Hydrological Functions using Digital Elevation Model (DEM) and Soil Conservation Service (SCS) Model

Abstract

The principal advance in GIS hydrological modelling that has occurred during the past several years has been the widespread availability of Digital Elevation Models (DEM) via Internet and CD-ROM and advances in the methods of processing them. Using digital elevation data, different models have been developed over the years that can automatically delineate a watershed and sub-basins (Garbrecht and Martz,1999).

In this study, the Surface Runoff Quantity was derived using Soil Conservation Service (SCS) Model, developed by the U.S. Soil Conservation Service in 1972. Curve numbers were determined by factors based on land use/cover from classified Enhanced Thematic Mapper (ETM) and soil groups. The results show that the simulated runoff processes are in good agreement with measured runoff, and the accuracy of the simulated runoff was over 75%. This clearly demonstrated that integration of Remote Sensing, GIS and SCS model provided a powerful tool for runoff simulation of small watershed in the Study Area