ROCK KOSHKONONG LAKE DISTRICT Lake Dredging Project

Lake Koshkonong Dredging Project Phases of Work PHASE I PHASE I –Establish goals and objectives –Confirm funding sources –Assess feasibility of obtaining permits PHASE II PHASE II –Confirm areas and sequence of dredging –Assess physical and chemical characteristics of sediment –Confirm disposal methods and areas –Prepare options analysis –Prepare dredging plans and specifications –Obtain permits PHASE III PHASE III –Competitive bidding process –Services During Construction (as requested)

RSV ENGINEERING, INC. Illustrations & photos courtesy of Keene Engineering

RSV ENGINEERING, INC. Illustrations & photos courtesy of Keene Engineering

RSV ENGINEERING, INC. Illustrations & photos courtesy of Keene Engineering

RSV ENGINEERING, INC. Illustrations & photos courtesy of Keene Engineering

RSV ENGINEERING, INC. Illustrations & photos courtesy of Keene Engineering

General Information Regarding Hydraulic Dredging A 8”-10” hydraulic dredge (diameter of discharge hose) can dredge cubic yards per hour. A 8”-10” hydraulic dredge (diameter of discharge hose) can dredge cubic yards per hour. A 12”-14” hydraulic dredge can dredge up to 500 cubic yards per hour. A 12”-14” hydraulic dredge can dredge up to 500 cubic yards per hour. A lake the size of Lake Koshkonong may require the use of multiple dredges. A lake the size of Lake Koshkonong may require the use of multiple dredges. The cutter head is guided through the use of GPS, underwater cameras, and visual aids. The cutter head is guided through the use of GPS, underwater cameras, and visual aids. Slurry (sediment & water) can be pumped about 3,000 feet before a booster pump is required. Slurry (sediment & water) can be pumped about 3,000 feet before a booster pump is required.

General Information Regarding Hydraulic Dredging Slurry is generally pumped at a min. flow rate of 14 feet/sec to allow transport of gravelly material. Slurry is generally pumped at a min. flow rate of 14 feet/sec to allow transport of gravelly material. Slurry can be pumped into sedimentation basins, lake structures, or geo-bags. It can also be transported to landfills, farm fields, etc. Slurry can be pumped into sedimentation basins, lake structures, or geo-bags. It can also be transported to landfills, farm fields, etc. The umbilical (discharge hose) will be floated for several hundred feet before going under the water. The umbilical (discharge hose) will be floated for several hundred feet before going under the water. Fishing will be impacted in the close proximity to the dredge. Fishing will be impacted in the close proximity to the dredge. Hydraulic dredging minimizes turbidity (suspended solids) in the water over the use of alternative dredging methods. Hydraulic dredging minimizes turbidity (suspended solids) in the water over the use of alternative dredging methods.

Dredge Rates Hours Required To Dredge 1 Acre at Various Depths and Rates DredgeQuantity Dredge Quantity Per Hour Depth cu yds 100 cy/hr 200 cy/hr 300 cy/hr 400 cy/hr 500 cy/hr (ft)(yds)(hrs)(hrs)(hrs)(hrs)(hrs)

Dredge Rates Dredge Depth = 0.5 feet % Lake to Dredge 24-Hour Days Required DredgeArea 100 cy/hr 200 cy/hr 300 cy/hr 400 cy/hr 500 cy/hr (%)(acres)(days)(days)(days)(days)(days)

Dredge Rates Dredge Depth = 1.0 feet % Lake to Dredge 24-Hour Days Required DredgeArea 100 cy/hr 200 cy/hr 300 cy/hr 400 cy/hr 500 cy/hr (%)(acres)(days)(days)(days)(days)(days)