BASIN HYDROLOGY AND SUBSTRATE CONTROLS ON MOUNTAIN RIVER MORPHOLOGY IN THE HIGHLANDS OF THE APPALACHIAN PLATEAU

Processes that govern mountain river systems are poorly constrained. Rivers in mountainous regions are closely coupled to hillslopes, experience drastic changes in available energy and substrate, and have flashy hydrologic regimes. In order to understand the relationship between driving and resisting forces in a mountain river, data were collected from 68 reaches along two streams draining less than 500 km² in the Appalachian Plateau of West Virginia. Data collection included channel surveys, measurements of bankfull width, pebble counts, and use of digital elevation models. Increases in bankfull width correlated with increases in drainage area in concurrence with other mountainous regions. Unit stream power fluctuations reflect systematic reach scale adjustments of channel slope to longitudinal variations in substrate resistance and sediment supply. Longitudinal trends of unit stream power, substrate resistance, and channel morphology suggest that modeling of mountainous, but fluvial-dominated, landscapes may be possible if attention is paid to the distribution of resistant lithologies.