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On a hill, Duluth collaborates to slow water's flow

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Richard Axler
Richard Axler, senior research associate in Limnology and Water Quality at the University of Minnesota Duluth, stands along Amity Creek in eastern Duluth and talks about how the Graves Road project is affecting the flow of water into the creek during large rain events.
MPR Photo/Derek Montgomery

On a warm, sunny afternoon, University of Minnesota scientists Richard Axler and Jesse Schomberg stroll along a stretch of Amity Creek on Duluth's east side, pointing out various restoration efforts — an enormous stabilizing bank of rocks enclosed in wire, two new culverts and a stone-lined channel.

"We think the road and little valley washed out during a hundred-year storm in 1946 and had been bleeding mud for 60 years," says Axler, a researcher with the U of M Duluth's Natural Resources Research Institute.

On this day, the repaired trout stream flows lazily across rocks toward the Lester River and on to Lake Superior. But during a big rain, so much water rushes from streets and driveways and rooftops into the creek — listed as "impaired" by the Minnesota Pollution Control Agency — it becomes a torrent. After a storm in August, a 13-year-old boy drowned in an Amity swimming hole.

Controlling water during storms in Duluth is a difficult enterprise. Not only does the city contend with steep terrain but its soil is loaded with clay, which means it doesn't absorb water well and is highly erodible. Stormwater flows fiercely, sometimes even overwhelming the city's sanitary sewer system (a problem being addressed with several new overflow tanks), and is routed as much as possible through underground lines leading in myriad directions, including to Amity Creek.

Chris Kleist
Duluth city project coordinator Chris Kleist peers into one of the large catch basins the city has built to trap sediment that otherwise would flow into Lake Superior.
MPR Photo/Jennifer Vogel

Considering the creek's volume, it was important to fix the washout and reduce the sediment flowing downstream to Lake Superior. The university and the city of Duluth teamed up for the effort, which was partly funded by a $100,000 grant from  Ron Weber, a former Duluthian who made his fortune importing Rapala fishing lures.

"Weber money funded the engineering design and the city brought equipment and people," says Axler. "The city was a critical partner in this and they brought it to our attention. City public works staff really pushed hard for a couple of years to get the resources for the project. It's great when you are asking for resources all the time and then actually get them. It's nice to have a stakeholder partnership work as this one did."

In fact, Duluth is finding all kinds of innovative ways to address the difficult issue of runoff volume and quality, such as encouraging permeable parking lots and maintaining a series of 19 enormous concrete sediment catch boxes at the bottom of Duluth's hill. Some of the boxes are so large — one along I-35 is a quarter mile long — the city uses a Bobcat to clean them out every year or two. "I don't know of any other cities that use basins like we do," says Duluth project coordinator Chris Kleist. "Other cities tend to have ponds."

"Fishing in town, if you know what you're doing, can be good."

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 includes a long list of partners — nearby cities, St. Louis County, the Fond du Lac Band of Lake Superior Chippewa, the university and others.

Mainly the group focuses on educational efforts, such as environmental workshops for snow plow drivers and the people who maintain turf in the parks during summers. "Some communities were reluctant to be part of the stormwater group at first," says Schomberg, who works with the Minnesota Sea Grant program, a member of the team. "But over time, people got to know each other and got used to the idea. Some of the benefits are really unquantifiable. It's about relationships."

Rocks
Rocks slow sediment flow into Amity Creek when heavy rains send lots of water from city streets down the stream bed.
MPR Photo/Derek Montgomery

There are 16 designated trout streams, including the Amity, inside Duluth's city limits. The creeks are largely an unheralded amenity, according to Kleist, who is trying to land a separate grant to fix Buckingham Creek, which runs through Enger Park Golf Course. "These are one of the real treasures of the city," he says. "It's amazing how many people don't know they're there. Fishing in town, if you know what you're doing, can be good."

The objective with stormwater in Duluth is to slow it, settle out its sediment, and even cool it so it's less harmful to the fish that live in the streams. "We are trying to smooth out the spikes," says Kleist. "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."

In late 2010, the city passed a new land use plan called the Unified Development Chapter, which stands to help water quality by emphasizing environmentally-friendly design and erosion control, and restricting the creation of impervious surfaces. Between 1990 and 2000, according to one study, Duluth was one of the only sizeable cities in the state to reduce its percentage of such surfaces.

In Duluth — because of all that clay — creating a permeable surface requires more effort than it does in some other places. Because water doesn't naturally percolate down into the ground, a permeable parking lot at the College of St. Scholastica actually has an impervious surface a few feet below it that collects and funnels runoff. Similarly, at the U of M Duluth, a parking lot was built with storage tanks underneath to catch the water, filter it and cool it before gradually releasing it.

Checking rain barrel
Todd Carlson, water quality specialist with the city of Duluth, inspects a rain barrel that captures excess water coming off a home during rain storms. The system distributes the water slowly so the ground can absorb it.
MPR Photo/Derek Montgomery

Schomberg lauds the new code, which regulates landscaping around parking lots and gives parking space credits to developments near transit lines. "I went to every hearing and submitted lots of comments," he says. "It is what I wanted it to be. There is more in there than I thought there would be."

Beyond that, Kleist, Schomberg, Axler, lead researcher Valerie Brady and a handful of other partners just completed a three-year experiment to see what kind of impact individual homeowners with rain gardens and barrels could have on stormwater flowing into Amity Creek, the largest watershed in the city.

Starting in October 2007, the team monitored runoff from three streets in the Lakeside neighborhood for a year. The next year, the team — with the help of residents and the Conservations Corps Minnesota — installed conservation measures along one of the streets. They planted 250 trees and shrubs and put in 22 rain barrels, five rain gardens, 12 overflow storage basins and two swales. They also reconstructed a stormwater ditch.

Berm
A garden surrounded by a small berm was planted in front of a residence on Idlewild Street in eastern Duluth. The garden and berm collect rainwater that would have normally flowed into storm sewers and ultimately into Lake Superior.
MPR Photo/Derek Montgomery

The third year was spent measuring the difference in runoff volume and quality between the street with conservation measures and the two streets without them. "There were definitely benefits in the treatment group," says Kleist. Comparing one year to another was tricky, given varying rain amounts and temperatures and other factors. And the experiment was geographically small. Yet, says Kleist, "When we looked at the total volume throughout the season, it was down slightly."

This will be good information to have when talking with residents about the benefits of conservation, says Kleist. Already, the project is making a difference. When residents were surveyed early in the study, according to its final report, only half "knew that there was a stream five blocks away, and many of these folks incorrectly identified it as the Lester River (which is the next stream over)." Only 22 percent realized their stormwater flows into Amity Creek before going into Lake Superior.

By the end, however, there was, "an increase in understanding by treatment‐street residents of where stormwater flowed to and what it affected, and an increase in willingness to accept at least some responsibility for stormwater runoff." Even residents outside the study area were asking for rain barrels, Kleist said.   This could be good news for Amity Creek, says Axler, who is part of the Weber Stream Restoration Initiative, recently awarded close to $850,000 from the national Great Lakes Restoration Initiative. With the money, the group will continue its Amity monitoring efforts and will build online resources for residential stormwater planning and ditch design. Progress can be followed on another of the U of M and city's joint projects, the Lake Superior Streams website.

Having the U of M and other colleges around makes Duluth a more progressive city, says Kleist. "They are great to work with. We try to work together on projects and coordinate educational programs so we're all saying the same thing. Younger students are a little more environmentally conscious," he adds. "They are more pro-active about their own environmental impact."

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