Effects of Urbanization on Geomorphic Stability of Watersheds

Despite the U.S. Environmental Protection Agency's able stewardship that has led to major strides in the improvement of the quality of natural streams since the passing of the Clean Water Act, forty percent of the nation&s waters are still categorized as impaired. Nationally, sediment related impairments form one of the top five groups for these streams to be listed on the 303(d) list. Sediment impairments are a direct outcome of poorly thought out stream stabilization measures and lack of emphasis on sustainable water resources development techniques over the last three decades. Although low impact development has finally started to become increasingly popular, corrective measures must still be taken to restore urban streams that have already been impacted. The goal of the project on which this paper is based, is to develop a set of predictive protocols that could be used as a key to future land use management with a view to preserving the aquatic and wildlife habitat. Presently, the paper provides a brief overview of available channel-stability assessment methods for applications in streams located in Midwest, and sets the stage for examining the effects of urbanization on the geomorphic stability of streams. To quantify the relationship of urbanization and stream-bank stabilization, two large southeastern Michigan watersheds are strategically chosen. One of the watersheds is largely urban while the other is largely rural, and thus provides good benchmarks. It is hoped that a final outcome of this study would provide additional data points that would be beneficial in reactive restoration measures of urban streams. Preliminary findings will be presented directly in the conference presentation.