Duluth collaborates to improve water quality

On a dry, sunny day, Amity Creek on Duluth's east end looks like your average trout stream. A small flow of water crosses large rocks on its way to the Lester River and on to Lake Superior.

But after a big rainstorm, like the one Duluth experienced last Tuesday, the Amity turns into a muddy torrent. So much so that a 13-year-old boy apparently drowned after the recent storm in an Amity swimming hole. Searchers are still looking for his body.

Given Duluth's steep terrain and the non-absorbent nature of its soil, scientists say the creek has probably always swelled and rushed after a big rain. But the city's many impervious surfaces--typical urban streets and driveways and rooftops--also contribute to the flow.

To mitigate its impact on the storm water that flows into Lake Superior, the city is finding innovative ways to control water volume and improve quality, such as discouraging impervious surfaces and maintaining a series of enormous concrete sediment catch boxes at the bottom of Duluth's hill.

What's interesting is that Duluth is searching for solutions in an unusually collaborative manner. For almost a decade, the city has been part of an informal group called the Regional Stormwater Protection Team, which involves a long list of partners including St. Louis County, the Fond du Lac Reservation and the University of Minnesota Duluth. The group works to coordinate education efforts.

[image]

For Duluth, the overarching goal is to slow storm water, settle out its sediment, and even cool its flow so it's less harmful to the fish that live in the city's 16 designated trout streams. "We are trying to smooth out the spikes," says Duluth project coordinator Chris Kleist, who chairs the protection team, while showing me around town on Monday, the day before the latest storm. "We are trying to slow the water down. It might be the same volume, but it will be released over a period of time. We're trying to create more of a natural runoff situation."

Recently, Duluth joined forces with the Weber Stream Restoration Initiative, which is headquartered at the U of M and partially funded by Ron Weber, a Duluth native who made his fortune importing Rapala fishing lures. Together, Duluth and the Weber team fixed a patch of road crossing the Amity that washed out in the 1940s and had been releasing mud into the creek for decades.

Duluth, the Weber team and others also just completed a three-year experiment, which involved the city's Lakeside neighborhood, whose storm water flows into Amity Creek. They measured runoff from three streets for a year, then during the second year added rain gardens and rain barrels to houses along one of the streets. The third year was spent measuring the difference in runoff volume and quality between the street with conservation measures and the streets without them.

The report is in the process of being finalized, but Kleist says, as he trudges through a vegetated water control trench behind the row of houses with rain gardens, "There were definitely benefits in the treatment group." Comparing one year to another can be tricky, given differing rain conditions. And the experiment was geographically small. Yet, says Kleist, "When we looked at the total volume throughout the season, it was down slightly."

One of the more exciting outcomes of the study, he adds, is that local residents have become more aware of water conservation, even requesting their own rain barrels. "There was more interest after the fact," says Kleist.

• Annandale watches special session for broadband help
• DNR pushes ahead with its groundwater planning
• Broadband providers seek $44 million from state fund
• Shifting rain could be lowering groundwater