Topography plays an important role in the distribution and flux of water and energy within natural landscapes. Many topographic parameters for hydrologic, water resources and environmental investigations can be computed directly from a Digital Elevation Model (DEM). This automated extraction of topographic parameters from DEMs is recognized as a viable alternative to traditional surveys and manual evaluation of topographic maps, particularly as the quality and coverage of DEM data increases. This paper presents capabilities and limitations of DEMs in water resources modeling support. Specifically, issues of data availability, quality and resolution, as well as capabilities and limitations in automated extraction of topographic parameters from DEMs, are discussed. Finding on the latest research results regarding the reduction of distributed subcatchment properties into a representative value for the subcatchment will also be presented.