1. Limnological Research Center, University of Minnesota, Minneapolis, MN 55455
2. Minnesota Pollution Control Agency, St. Paul, MN 55155
3. Department of Civil and Mineral Engineering, University of Minnesota, Minneapolis, MN 55455
4. Current address: James M. Montgomery Consulting Engineers, 545 Indian Mound, Wayzata, MN 55391
5. Current address: U.S. Geological Survey, District Office, 2280 Woodale Drive, Mounds View, MN 55112