This project was initiated in 1989, by the MCWD, with assistance from the Minnesota Pollution Control Agency (MPCA) through a Clean Water Partnership (CWP) grant. The overall framework for the project included: a diagnostic study to characterize and quantify the causes contributing to the decline in water quality in the lake; the development of numerical water quality goals for the lake; and the determination of performance standards for a remedial plan to improve water quality to achieve the desired goals. A Phase II study was also conducted which evaluated various alternatives for water quality goals set forth in the diagnostic study. These studies were undertaken with the support of the municipalities contributing runoff to Long Lake, assisted by a citizens advisory committee comprised of representatives for the city councils and other interested parties.

The feasibility study identified three projects that will improve the water quality of Long Lake. The first project is the construction of wet detention basins to reduce the annual loading of nutrients and sediment delivered to Long Lake via runoff from the northern watershed. Phase I resulted in the construction of a 4.5 acre two cell pond on the NE tributary south of Deer Hill Road in Medina. A 2.6 acre two cell pond south of County Road 6 in Orono will be constructed for Phase II.

The second project identified in the feasibility report is alum treatment of Long Lake to seal the lake sediments and reduce internal phosphorus loading. Alum removes phosphorus from the water by forming an aluminum phosphate precipitate or by sorption of phosphorus on the surface of polymerized aluminum hydroxide. By allowing the appropriate amount of alum to reach the sediments, the phosphorus rich sediments supplying the `internal loading' can be deactivated for potentially long periods of time improving the trophic state of the lake.

The final project is the enhancement of existing sedimentation basins in the City of Long Lake Park to reduce the load of nutrients and sediment to Long lake from the two major storm sewered subwatersheds.

Long Lake Project Specifications

• Location: Long Lake, Orono & Medina, Minnesota
• Completed: 1996 (Phase I & II); 1998 (Phase III)
• Contractors: Carl Bolander & Sons (pond construction)
• Sweetwater Technology (alum treatment)
• Engineer: Wenck Associates, Inc.
• Cost: $2.2 million
• Funding: MCWD Ad Valorem Tax & Communities to share in O&M cost
• Deer Hill Road Site: 71,1000 cubic yards excavated; 35 acre feet; 4.6 acres
• County Road 6 Site: 25,000 cubic yards excavated; 15.2 acre feet; 2.5 acres
• Park Ponds/Wetlands Site: 10,000 cubic yards excavated; 4 acre feet; 0.85 acres; fish barriers
• Alum Treatment: 540,000 lbs to treat 181 acres