1. Download 1 Arc-Second SRTM Digital Elevation Model (DEM) from USGS Earth Explorer | Part 2
Watershed delineation is the process of identifying the boundary of a watershed, also referred to as a catchment, drainage basin, or river basin. It is an important step in many areas of environmental science, engineering, and management, for example to study flooding, aquatic habitat, or water pollution.
Digital Elevation Model (DEM) is the basic unit, which is used as an input in ArcGIS to delineate watershed. After delineation of watershed, its physical characteristics can be obtained like its area, stream network, length of a river, slope and other parameters. watershed delineation plays important role in hydrological mdoeling.