Extraction of Drainage Pattern and Watershed from SRTM Data Using GIS Tools: A Case Study

Abstract

This paper proposes a fast and an inexpensive method for delineating the drainage and watershed of a sub-basin. Planning of the water resource management is evolving from simple local-scale problems toward complex spatially explicit regional scale. Such problems have to be addressed with distributed models that can compute runoff and erosion at different spatial and temporal scales. In general, watershed can range from as little as one hectare to hundreds or thousands of square kilometers. The spatial scale for which a model is designed can influence the specific processes of hydrological cycle. This paper seeks to estimate watershed and drainage delineation from topographical map using shuttle radar topographical mapper digital elevation model (SRTM - DEM) in ArcGIS 10. A simple automatic delineation was carried out at sindapalli uppodai sub basin of vaippar River basin; Tamilnadu, India. Results showed that by using watershed function in ArcGIS 10 for watershed delineation in the sindapalli uppodai sub basin can be determined. This work is mainly a case-study of simple applicability of GIS as a tool of watershed delineation and drainage extraction. The total area of watershed calculated from watershed layer is about 147.4 sq. km but, according to topomaps it is works out to be 143.7 sq. km.  The drainage pattern delineated from the topomaps is synchronized with the DEM based delineation.

Keywords: SRTM, DEM, ArcGIS, drainage, watershed