Terrain Analysis Using Digital Elevation Models in Hydrology

This paper describes methods that use digital elevation models (DEMs) in hydrology, implemented as an ArcGIS toolbar using Visual Basic and the ESRI object library. I describe generalized channel network delineation to objectively estimate drainage density and by using terrain curvature accommodate spatially variable drainage density. The multiple flow direction field determined from a DEM also serves as a basis for routing overland and topographically driven subsurface flow useful in water quality, erosion and terrain stability modeling. New DEM derived quantities, such as downslope influence, upslope dependence, decayed accumulation, downslope accumulation and transport limited accumulation are illustrated.