1. Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Washington, 201 More Hall, P.O. Box 352700, Seattle, WA 98195-2700.
2. Research Scientist, Center for Urban Waters, Univ. of Washington, Tacoma, 326 East D St., Tacoma, WA 98421.
3. Associate Professor, School of Environmental and Forest Sciences, Univ. of Washington, Anderson Hall Box 352100, Seattle, WA 98195-2100 (corresponding author).