Establishment of channel networks in a digital elevation model of the prairie region through hydrological correction and geomorphological assessment

摘要

Building channel networks in flat regions of digital elevation models (DEMs) is important for watershed delineation and hydrological modeling, particularly for areas with gently-sloped terrain, such as the Canadian Prairies. Existing drainage analysis methods cannot effectively address the spatial correlations of elevation across the flat regions, and the quality of the DEM-derived channel network is mainly evaluated through visual inspection. In this study a hydrological correction method is developed that integrates elevation information from both the existing digital channel network and the original DEM. A set of geomorphological indices is then introduced for quantitative evaluation of DEM-derived channel networks from the perspectives of flow direction and drainage pattern. Both the DEM correction and network assessment methods are implemented in a GIS environment. Their performance is demonstrated through a case study in southern Saskatchewan, Canada. The generated channel network is consistent with the known hydrological information and contains fewer parallel channels compared with existing methods. The developed methods could be valuable for a wide range of applications using the Canadian Digital Elevation Data (CDED) within the context of the Canadian Prairie region. \ua9 2013 Canadian Water Resources Association.