The Minneapolis Chain of Lakes are among the most visited natural resources in the state. Millions of people come to the shores of these lakes each year to enjoy their beauty and serenity.
It’s not easy for a lake surrounded by such highly urbanized area to stay clean and healthy. Stormwater runoff that flows off the landscape ends up in these lakes, and the more roads, roofs and driveways there are, the more pollutants this rain water picks up along the way.
Yet these lakes remain some of the healthiest urban lakes in the nation. This didn’t happen by accident. In the early 1990’s a coalition of groups called the Minneapolis Chain of Lakes Clean Water Partnership undertook one of the largest urban water quality restorations in the nation, resulting in some dramatic improvement in lake health still evident to this day. In addition to the Minnehaha Creek Watershed District (MCWD), the partnership included the cities of St. Louis Park and Minneapolis, the Minneapolis Park and Recreation Board, Hennepin County, Minnesota Pollution Control Agency, and an active citizens advisory committee.
The partnership formed in response to growing concerns over the quality of the Chain of Lakes. A thorough study of the lakes revealed a significant degradation of their water quality during the 1950’s and 1960’s that had not improved. The pollutant of particular concern — then as in now for most lakes in the watershed — was phosphorus, which promotes algae growth. The study estimated the lakes’ phosphorus levels were more than double pre-settlement conditions.
To reduce the amount of phosphorus flowing into the Chain of Lakes, the partnership used a combination of structural improvements, improved landscaping practices and public education to address pollution in the lake. In particular it tapped the unique ability of wetlands to remove phosphorus from stormwater runoff (MCWD was one of the first organizations in the country to study the power of wetlands for this purpose) and built several new ones around Cedar Lake, Twin Lakes, and Lake Calhoun. Other techniques included restoring shorelines, using special chambers to remove grit from runoff, removing geese, conducting chemical treatments, and encouraging smart use of fertilizers and pesticides.
Within a few years measurable improvements in phosphorus and clarity were visible in Lakes Calhoun, Cedar and Harriet, which all met the goals set out by the partnership. Residents played a big role with improved lawn care practices, as the amount of pesticides measured in stormwater runoff went down by half.
By working together, the MCWD and its partners achieved significant and lasting results. This spirit of partnership continues to guide our efforts to bring the natural and built environments in balance across the watershed.