Analyses of watershed longitudinal/transverse profiles and stream-net structure using high-resolution DEMs

We applied DEMs at 1-m resolution (for small bare lands) and at 10-m resolution (for broad forested areas) in Japanese hills and mountains for quantitative analyses of longitudinal/transverse profiles of watersheds and stream-net structure, with special attention to watershed evolution and regional relief. Many statistical morphometric parameters have distinct and consistent correlations with relief in both the 1-m and 10-m DEM areas, and most topographic characteristics of watersheds in the high-relief areas are simpler and more organized than those in the lowto middle-relief areas. The results of this research indicates that high-relief terrains have more mature conditions close to equilibrium, although some other morphometric parameters also indicate the effects of marked differences in bedrock strength. In addition, very detailed stream-net structure represented by 1-m DEMs significantly reflect local factors such as proximity to the trunk stream, especially if channels are at the early stages of erosion, while those represented by 10-m DEMs correspond more simply to regional relief.