Urban Storm Water Runoff and Inland Lakes: A Tale of Two Cities Jarron D. Hewitt and Martin T. Auer Department of Civil and Environmental Engineering, Michigan Technological University, Houghton, MI Crystal Lake, Iron Mountain, MI Lake Alice, Fergus Falls, MN ECOSYSTEM HEALTH CONCERN: Coliform Bacteria and Nutrient Loading ECOSYSTEM HEALTH CONCERN: Eutrophication: Algae and Aquatic Macrophytes ECOSYSTEM HEALTH CONCERN: Oxygen Consuming Sediment and Winter Fish Kills ECOSYSTEM HEALTH CONCERN: COLIFORM BACTERIA AND NUTRIENT LOADING SOLUTION: DIVERSION OF STORM SEWER INPUTS ECOSYSTEM HEALTH CONCERN: SEDIMENT OXYGEN DEMAND AND WINTER FISH KILLS SOLUTION: DREDGING OF LAKE SEDIMENT AND ADDITION OF AERATORS ECOSYSTEM HEALTH CONCERN: EUTROPHICATION: ALGAE AND AQUATIC MACROPHYTES SOLUTION: DIVERSION OF STORM SEWER INPUTS Crystal Lake Menominee River STORM CAD Pipe Layout pipe locations pipe lengths Design Data drainage area elevations street layout Storm Data idf curve land use design storm Storm CAD calculates area-specific runoff Pipe Design Characteristics (diameter, flow) Profiles of Pipe Network (slope, ground cover) GOALS OF STORM SEWER DIVERSION: Reduce coliform bacteria inputs and improve swimming health of the lake Remove inputs of phosphorus which stimulates growth of aquatic organics Manage the 10-year design storm runoff from Iron Mountain and Kingsford Find the least expensive option for storm sewer diversion STORM CAD PROCESSES: Design Storm Diameter North to East Pipe Diameter East Pipe to Junction Chamber Diameter New Pipe Junction to 1 st Open Channel Open Channel New Pipe to Detention Basin (depth) Open Channel Detention Basin to River (depth) 2-year48 inches60 inches72 inches66 inches60 inches 5-year60 inches72 inches 60 inches 10-year60 inches72 inches78 inches 60 inches 25-year60 inches78 inches84 inches 60 inches 50-year72 inches78 inches84 inches90 inches66 inches 100-year72 inches84 inches90 inches 66 inches DESIGN 1: Uses existing open channel and explores the possibility of using additional open channel to reduce the amount of concrete pipe needed to convey storm water. Existing Open Channel/Drainage Basin Proposed Storm Sewer PipeProposed Open Channel DESIGN 2: Uses existing open channel connected with the proposed storm sewer. This design involves 2,580 feet of pipe in addition to what is needed for design 1. GOALS OF AERATION: Improve oxygen conditions in the lake to allow the reestablishment of a fishery Offset sediment oxygen demand from organic decomposition GOALS OF SEDIMENT DREDGING: Cost including concrete pipe, pipe installation, and contractor mobilization DESIGN 1: $3,870,517 DESIGN 2: $4,829,390 COST OF STORM SEWER DIVERSION: Removal of oxygen consuming sediment to reduce phosphorus release and sediment oxygen demand Restore lake bottom to natural sand and improve lake depth The majority of work done has been on Crystal Lake. Details of the work done towards restoration of this lake are shown at right. Jarron Hewitt will be continuing work on Lake Alice post-graduation with Interstate Engineering in Fergus Falls.