Impact of Digital Elevation Model resolution on stream network parameters

Digital Elevation Models (DEMs) have been widely applied to efficiently derive topographic attributes used in hydrologic modeling. However DEMs are not free of errors and limitation. This paper investigated the effects of digital elevation model resolutions (40 m, 50 m, 60 m, 70 m, 80 m and, 90 m) on elevation, number and area of subbasins and area of watershed. Bilinear interpolation method is utilized to create coarser resolution of DEMs from 30m grid size. It is found that data aggregation has little influence on elevation of the study area. There is definite correlation that can be found between number and area of subbasins and DEM grid size in this study area. The results suggest that primary process can be very important and a profound understanding on this would ensure that hydrologic model uncertainty be rigorously assessed.