City, parks and watershed district team up to repair Minnehaha Creek, clean up Lake Hiawatha

Minnehaha Creek has long been treated like a glorified drainage ditch as it flows downstream from Lake Minnetonka through south Minneapolis, dumping street runoff into the Mississippi River. A new partnership seeks to redefine the creek’s relationship with the people who live along its banks and play in the lakes fed by its polluted water.

Modeled after the 1991 Clean Water Partnership that introduced water quality monitoring to the Minneapolis Chain of Lakes, the new agreement brings together the city of Minneapolis, Park Board and Minnehaha Creek Watershed District. It proposes engineering curves back into the artificially straightened Minnehaha Creek, and three stormwater treatment projects targeted at the densest underground pipe systems in south Minneapolis.

The ultimate agenda: clean up Lake Hiawatha and pull it off the state’s impaired waters list, where it has languished for 22 years.

“We’ve experienced the extremes of drought and flooding and we know that they are getting more extreme,” said James Wisker, district administrator of the Minnehaha Creek Watershed District. “It’s taxed our infrastructure and damaged our natural systems. It’s also brought attention to old land use decisions that are still impacting us today, like the historic filling of our region’s wetlands to make way for growth and development.”

Residents have expressed concerns about the sustainability of the city’s residential and recreational environment. Water problems have increasingly interfered with the quality of life in south Minneapolis, with basements flooding when it storms and high levels of E. coli cutting beach season short.

The Minnehaha Creek watershed covers 178 square miles of the metro, encompassing 29 communities of Hennepin and Carver counties and 120 lakes and streams including Lake Minnetonka. Everyone who lives in the watershed pays taxes to the watershed district, which is responsible for managing the water’s health.

The biggest obstacle to the district’s work is their inability to control what happens on land. Nevertheless, litter, dirty runoff and the loss of land to development affect water. So over the past decade, the watershed district spent heavily on co-developing new parks, nature preserves and even housing complexes with stormwater treatment features in Edina, St. Louis Park and Hopkins.

“We’re going to continue to work together in perpetuity, no matter who is in the roles that we all are filling right now, to continue to work to improve water quality and the entire Chain of Lakes and the creek corridor until there isn’t anything left to do, because that’s what we need to do,” said Park Board Commissioner Steffanie Musich, who has long advocated for improving the water quality of Minnehaha Creek.

The partnership is using Lake Hiawatha as a barometer of progress because it’s the last lake in the Minnehaha Creek watershed before its waters flow into the Mississippi River.When there’s water in the creek, it flushes Hiawatha’s system, and bacteria concentrations in the lake could either increase or decrease based on the creek’s water quality, according to the Park Board’s latest water resources report. There are also seven stormwater outfalls surrounding the lake.

Despite all the efforts to improve water quality upstream, in 2022, Hiawatha Beach closed for nearly two months due to excess E. coli. Over the past 10 years it has tallied the highest number of closures of all Park Board beaches. Hiawatha also is the only Minneapolis lake where zebra mussels have been detected on sampling plates, according to the Park Board’s aquatic invasive species report, which blames the infestation on Lake Minnetonka via Minnehaha Creek.

Friends of Lake Hiawatha, a neighborhood group focused on repairing the wildlife habitat around Lake Hiawatha, has been pulling plastic litter out of its lakeshore grasses for years. The group is advocating for trash to be included as one of the pollutants measured and monitored by the Minnesota Pollution Control Agency. The city now lists trash as a pollutant of concern.

There are other serious water issues in the vicinity. Residential yards and basements around Solomon Park and Lake Nokomis would flood badly in wet years, and neighbors’ demand for answers eventually led to an investigation of historical records showing how filling wetlands in the Minnehaha Creek floodplain in the 1910s created neighborhoods perched atop water-retaining peat deposits.

“It’s been amazing that they’ve done all this work upstream, which does help Minneapolis and it does help Lake Hiawatha, but targeting near us will be really beneficial, to make sure we’re doing the most that we can to support climate change [resilience] in the areas that we see all the time,” said Koski.

Minnehaha Creek dips around a set of tennis courts at 52nd and Morgan Avenue S. and trickles beneath an idyllic wooden bridge. One of the most obvious signs of impairment here is a crumbling concrete spillway that shoots stormwater runoff straight into the creek. Another is along the creek’s edge, where years of water rushing down has scoured away the bank, and tall trees have begun to lean for lack of a solid anchor. Excess sediment dumped into the creek here travels down to Lake Hiawatha, said Michael Hayman, the watershed district’s director of project planning.

The stretch of the creek between Penn and Morgan avenues is one of three focus areas comprising the first phase of the creek restoration partnership. It will include replacing the concrete spillway with some kind of cascading rain garden. New wetlands and curving of the creek are also planned for Nicollet Hollow, where the creek forms a bowl around a cluster of houses before it hits Nicollet Avenue, and at Cedar Avenue just upstream of Lake Nokomis.

The spots were chosen because they are where the densest system of pipes drains directly to the creek, said Hayman, so installing stormwater management features here would theoretically have the greatest impact on downstream waters. If these projects are constructed along with other efforts, like keeping yard waste out of drains, the state could take Lake Hiawatha off its roster of impaired waters within the next decade, he said.

“There’s two times when people are always thinking about the creek. Number one when the creek is flooding, number two when all of a sudden there is no creek, it’s just a dry walkway full of rocks,” said Jonathan Heide, who lives a few blocks away from the creek in the Field neighborhood and often runs along its banks. During the height of the pandemic, he ran the creek’s north bank all the way up to Gray’s Bay Dam at Lake Minnetonka, then back down its south bank to Minnehaha Falls. It took him several days to piece it all together, but along the way he got to see bridges and golf courses, parts where the creek had been used like a parking lot runoff dump, and segments that had been restored to a natural arabesque.

The city signed on to the partnership this month. Once the Park Board and watershed district also ratify it, feasibility studies will begin on the first three projects, which will define costs.