Feb 29 - Dr. Glenn Moglen, Department of Civil and Environmental Engineering, National Center for Smart Growth Research and Education, University of Maryland
"Impervious Surfaces and Ecological Integrity: Threshold-based Policies, Data Limitations, and Unintended Consequences"
Urbanization has long been identified as the source of amplified flooding, poor water quality, and other forms of environmental degradation. The use of percent impervious area to characterize the degree of urbanization within a watershed has become standard practice. Research suggests that negative impacts on the environment correlate well with impervious area in excess of 10 to 15 percent. Here we examine the large variance in imperviousness measurements that result from different methods and data sources. Additionally, we demonstrate complications arising from drainage network organization of imperviousness across the landscape. Finally, we investigate an optimization approach that approximates an ecologically-based imperviousness threshold policy. The optimization minimizes total stream length in excess of a threshold value. The resulting urbanization patterns suggest that unintended consequences of low density sprawl may follow from such policies.
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