Downstream Effects of Urbanization on Stillwater Creek, Oklahoma

Geomorphic effects of urbanization vary according to local conditions and with different ecoregions. This project evaluates the effects of urbanization on Stillwater Creek, located in central Oklahoma. The upper section of this basin is predominantly rural, while the downstream section is experiencing urban expansion. It was hypothesized that the channel morphology of the lower section would differ significantly from that of the upper section due to the location of the confluence of Boomer Creek, which brings urban runoff from the city of Stillwater. Statistical analysis of downstream trends revealed no significant change in the majority of response variables between upstream and downstream sections. However, local conditions (i.e,. riparian trees, cohesive bank materials, occasional woody debris jams, and entrenched nature) in this basin counter the possible effects of urbanization on channel morphology. Increasing urbanization was expected to reduce the sources of woody debris to stream channel and affect channel morphology. However, Stillwater Creek had thick riparian corridors dominated by trees, which helped protect stream banks. A downstream parabolic channel cross-sectional shape also helped explain why this stream channel did not change radically due to urbanization.