What is involved in the cleanup of Lake Nokomis and Lake Hiawatha?

The project will begin fall 2000 and is projected for completion in summer 2001. The project includes installing three wetland settling ponds adjacent to Lake Nokomis; installation of two grit chambers near Lake Nokomis; installation of an inflatable weir on Minnehaha Creek to keep pollution from entering Lake Nokomis; and intensive public education on the effects of high phosphorous lawn fertilizer, pet waste and other runoff hazards that affect water quality. Lake Nokomis will be treated with alum a non-toxic chemical that binds with polluting phosphorous, settling to the lake bottom.

How do the ponds work and will they stand out in the park?

Wetland settling ponds are an environmentally friendly, gravity-based method of cleaning surface water. Settling ponds receive storm water runoff from storm water drains. Phosphorous clings to the grit in the runoff and settles to the bottom of the ponds.

Nuisance algae blooms in Lake Nokomis are caused by excessive phosphorous. Most of the phosphorous originates in the local watershed and is carried by runoff. Other sources of pollution, like oils, pesticides and sediments, are also carried in runoff from the neighborhoods. The goal for Lake Nokomis is to remove 900 pounds of phosphorous per pond on an annual basis.

In terms of effectiveness, the wetland settling ponds installed at Lake Calhoun have prevented the growth of an estimated 180,000 pounds of algae by removing phosphorous. An estimated 30,000 pounds of suspended sediments were also removed. Lake Calhoun was recently given an A grade in water clarity and water quality.

The Lake Nokomis ponds will be landscaped with prairie and wetland plants, which will benefit from the phosphorous. The ponds’ design will be integrated into existing park land, enhancing the natural beauty of the park.

What do grit chambers do and are they effective?

Grit chambers are below-ground chambers that are part of the storm water drainage system. Two will be installed at Woodland Avenue and 50th Street and 53rd Street and Shoreview Avenue. At Lake Nokomis, a new type of grit chamber design will be used. The principle of gravity is used to design a circular prefabricated concrete holding tank that allows the grit and debris to sink to the bottom, keeping it from entering the lake.

What other strategies are being applied to clean up the lakes?

A number of actions are planned to work together in cleaning up the lakes, including carp removal later this winter from Lake Nokomis. Carp tend to stir up lake bottoms where the phosphorous has settled, hurting water quality and creating algae bloom.

Who’s involved in the cleanup?

The Blue Water Partnership, comprised of The City of Minneapolis, the Minneapolis Park and Recreation Board, and the Minnehaha Creek Watershed District, is implementing the recommendations of the Blue Water Commission’s 1998 report. The Blue Water Commission was formed by citizens from Nokomis East, Standish Ericsson, and Hale Page Diamond Lake neighborhoods, and the Citizen Advisory Committee (CAC)

Minnehaha Creek runs next to Lake Nokomis and through Lake Hiawatha.. The entire Minneapolis Chain of Lakes is part of the Minnehaha Creek Watershed, starting west of Lake Minnetonka and ending at the Mississippi River. Minnehaha Creek Watershed District is providing the majority of funding, and engineering and communication expertise for the Lake Nokomis/ Lake Hiawatha water cleanup.

MCWD is a small autonomous unit of government and the second largest watershed district in the metro region. MCWD works in partnership with cities, townships, and citizen groups to help improve the water quality in most of the lakes and streams in the watershed.

Will there be any traffic delays with construction of the grit chambers and the ponds?

According to the City and engineers for the project, there will be minor disruptions of traffic for a week at a time when the two grit chambers are installed. There should be no disruption to traffic when the ponds are built later.

Where can I find more information?

During the life of the construction project, this web site will be the primary source for providing regular updates. Neighborhood newspapers and newsletters will also be a good source of information.