COMPARING DEM-DERIVED STREAM CHANNEL LONGITUDINAL PROFILES ACROSS DATA RESOLUTIONS AND DIFFERENT LARAMIDE TERRANES

Fluvial stream channel longitudinal profiles (“stream profiles”) have been recognized to represent evidence of fluvial systems working toward an equilibrium state balancing the drivers of climate, geology, tectonics, and base level. Plots of elevation against distance and watershed area against slope have been used in the Black Hills to demonstrate two breaks in slope that are hypothesized to delineate three distinct erosional surfaces. The authors have developed GIS tools to streamline and simplify the process of generating stream profiles from digital elevation models (DEMs) and mapping watershed features onto these profiles. These tools were tested against existing profiles and slope/area analyses created using less automated methods for watersheds in the Black Hills.

These tools provide the capability to readily compare stream profiles created from contour sourced and lidar sourced DEMs and across resolutions, and among watersheds in the Black Hills and Laramide Range. Preliminary results show that prominent breaks in slope (“knick zones”) are evident in the same watershed across DEM data sources and resolution, and qualitative comparisons can be made among profiles from the different watersheds. Continued application of these tools should provide new insight as to the common surface history of Laramide terranes.