A Bid to Save Suburban Streams

Conservationists are working to protect trout streams pressured by urban development.

By Harland Hiemstra

To read or write about a trout stream is something different from being there. To splash in its cold springs and riffles is to feel like a child again; to rest on its shady bank and nibble fresh watercress is to forget age and time as the water speaks to your soul in its ancient purling tongues.

For the half of the state's population that lives in the Twin Cities area, experiencing the timeless charm of a trout stream anywhere nearby could become more of a literary exercise if losses of streams continue. Trout Brook, for instance, which wanders along the eastern edge of downtown St. Paul, hasn't lived up to its name within anyone's memory. Most of it was channeled through a culvert long ago. Golden Valley Creek, Purgatory Creek, Nine Mile Creek--no one knows for sure how many metro trout streams have been lost, because some disappeared before anyone kept track. Today, portions of only 15 streams in the seven-county metro area remain natural enough to support trout, and most stand in danger from urban development

Cities aren't very friendly to trout, which need cold, clean water to survive. Storm water runs off pavement, rooftops, and other impervious surfaces, warming the stream and degrading water quality. After a while--no more trout.

But it's not just the fish that suffer. Sensitive in terms of habitat needs, trout are an environmental barometer, indicating either a thriving ecosystem or biodiversity in decline. "You have to value them not only for the fishing they provide but for their existence," says Tom Schueler, executive director of the Center for Watershed Protection in Washington, D.C. "It's harder and harder to find natural stream systems in urban and suburban areas anymore. Keeping a stream like that has enormous value to society, so they can know what a real stream is like."

Bubbling Springs

The Mdewakanton Dakota say that long ago Buffalo Calf Woman rose from the bubbling springs of Eagle Creek and taught them how to pray and use the sacred pipe. Much more recently, those same fresh waters gave birth to a preservation effort focused on Twin Cities trout streams.

When the city of Savage received a development proposal to build housing and offices on the banks of Eagle Creek four years ago, some citizens welcomed the project as an addition to the local tax base. Others rallied around what they saw as a life-and-death struggle for the Minnesota River valley's only stream where trout could still reproduce naturally. The controversy spread from the local level to the Legislature. Lawmakers allocated $1.6 million for the Department of Natural Resources to purchase a narrow corridor along the stream. With funding in hand, DNR biologists set to work with the developer, local officials, and conservationists to create a management plan aimed at preservation.

Today, Eagle Creek is an experiment in progress. Surveying stakes mark future construction sites. Houses in various stages of completion line a suburban street that snakes along the contour of the bluff above the stream. Behind the houses, an earthen berm slopes away from the ridge, creating a grassy swale to keep storm water from running into the creek. On each bank of the creek's west branch, the DNR has purchased a 200-foot corridor to buffer the waterway from human impacts. Negotiations are under way to acquire a corridor along the stream's east branch.

The idea, says DNR fisheries biologist Jerry Johnson, is to create a mini-watershed around Eagle Creek to isolate it from development. Any rain falling outside the 400-foot corridor will be diverted away from the stream and into the nearby Minnesota River. Within this buffer zone, plantings of native vegetation and other streambank improvements will minimize the effects of runoff and erosion and re-create habitat closer to presettlement conditions.

No one knows for certain if these measures will save the stream. But the particular circumstances around Eagle Creek have Johnson feeling hopeful. The small size of the creek's watershed makes it manageable, and the housing developer has been cooperative. Local sandy soils allow for more infiltration and less runoff than heavier soils would allow. And the area's relatively flat topography lends itself to storm water diversion. Even if efforts should fail to preserve the fishery, the surrounding landscape will be in better shape than if development had proceeded as originally planned. And, of major significance for other trout stream preservation efforts, extensive monitoring of Eagle Creek will enable scientists to pinpoint the causes of any further degradation.

"This was an eleventh-hour decision," Johnson says. "It was an either you do it or you don't do it kind of thing. History has shown us that if we would have allowed development right up to the stream, we would have lost the stream. This wasn't our best option; it was our only option."

Top Six

Hoping to avoid such eleventh-hour decisions in the future, a group of anglers and DNR biologists issued a report last fall outlining the need for greater efforts to protect metro trout streams. They identified six of the 15 streams as deserving of special attention: Brown's Creek, Old Mill Stream, and Valley Creek in Washington County; a portion of the Vermillion River in Dakota County; Assumption Creek in Carver County, and Eagle Creek. As a result, several Twin Cities area communities are considering how to preserve this part of their natural heritage while accommodating urban growth.

Lakeville and Farmington, for instance, have launched a study to monitor the effects of storm water runoff on tributaries to the Vermillion River. Woodbury officials are wondering how they might modify plans for commercial and industrial development along Interstate 94 at the headwaters of Valley Creek. And Stillwater is looking at how to protect Brown's Creek from the effects of an 1,800-acre annexation of part of rural Stillwater Township to the city's boundaries.

"It's not a question of development versus no development here," says Sherri Buss, a natural resource specialist for Bonestroo, Rosene, Anderlik and Associates, an engineering firm hired by Stillwater to conduct the environmental review. "We have to find how development can happen here and still maintain the quality of Brown's Creek. It's a question of how development is designed and where it's appropriate."

Impervious Surfaces

Trout start to have problems when paved roads and other impervious surfaces cover more than 10 percent of a stream's watershed, Buss explains. That's roughly the equivalent of one house per acre. A typical urban area, on the other hand, is about 30 to 50 percent impervious. Water runs off these surfaces, carrying oil, fertilizer, road salt, and other pollutants into storm sewers, which usually empty into streams. The runoff pollutes and warms the fishery.

To reduce the amount of pavement, developers can plan narrower streets and shorter driveways. Clustering houses on smaller lots means shorter streets and more open space, which can hold water and allow it to infiltrate the soil rather than run into sewers. Woodlands, grassy swales along roads, and buffer zones of vegetation can also promote infiltration. Letting rainwater filter through the soil as near as possible to where it falls might compensate for developments that exceed the 10 percent impervious surface threshold, Buss says.

"The public preference has been for getting water off their property as quick as possible," Buss says. "Nobody was thinking about what the cumulative impact of that might be on resources like streams.

"The challenge for the engineers is to be able to model the effects of development and design new strategies for managing storm water. It doesn't mean no development can occur here. It means we have to be able to figure out how we can design to meet natural resource and community needs."

The strategies that Buss talks about came out of a series of meetings that included developers, engineers, city officials, and local residents along with anglers, conservationists, and biologists. Assembling people with diverse interests and asking them to come up with local solutions are critical to finding ways to preserve natural resources, she says.

"Trout stream issues are not just about technical considerations," Buss says. "They're about community values, and you need to bring together all the people who have an interest in it. Science and engineering just give you the options."

Will It Work

Whether the measures proposed, including a diversion of storm water away from Brown's Creek to McKusick Lake, will be adequate to save Brown's Creek remains uncertain. For one thing, the annexation area constitutes only about one-tenth of the stream's watershed. The actions of other communities in the watershed could negate anything Stillwater does. Furthermore, techniques to compensate for the influx of warm storm water into streams remain largely unproven.

"It's not easy to engineer away the effects of impervious coverage for trout," says Schueler of the Center for Watershed Protection. "Land-use limits are the only reliable and certain way to protect trout populations in urban areas."

Lee Ronning of the Land Stewardship Project agrees with Schueler. "We need to get smarter about how we're planning for growth and making use of the land," she says. "I'm convinced that without strong, sustainable planning and zoning, any other tool isn't going to be as effective at protecting what we want."

The Land Stewardship Project has been trying to develop legal tools that would more effectively limit urban sprawl and guide growth to prevent destruction of natural resources. Legislation mandating statewide land-use planning, for instance, could encourage communities to identify significant natural areas and direct development elsewhere. Conservation easements and other techniques that restrict land use could provide landowners with alternatives to subdividing and developing their property.

While Ronning says the goal is to guide development, not stop it, she also notes that growth does not always benefit the local tax base as communities commonly believe it does. Many studies indicate that the costs of development for local government--and ultimately taxpayers--often exceed additional tax revenues. Natural areas, on the other hand, incur few expenses.

"Trout don't go to school; you don't have to build schools or roads for them," Ronning says. "One thing we've learned for sure is if you're going to grow, it's going to cost you more, and that's not necessarily equal to the added tax base."

The Paradox

Natural amenities such as woods, wetlands, and streams help draw people beyond city limits to build homes. As more and more people follow, though, those natural attractions can be lost to development. That paradox lies at the heart of the conflict between urban growth and preservation. It might also offer insight into saving metro trout streams, says Tim Popple, manager of the Kinnickinnic River Watershed Project in Wisconsin.

Regarded as one of the finest trout streams in the upper Midwest, the Kinnickinnic flows through a landscape being pressured by people who work in the Twin Cities but want to live in a rural setting. "Most of the people moving into this area are moving here because they see this as a beautiful resource, so the last thing they'd want to do is destroy it," Popple says. "You need to educate those people and show them you can't just build houses on quarter-acre lots, all with their own septic systems." When people understand the value of a trout stream, they're more likely to demand alternative developments such as cluster housing or new approaches to managing storm water. That's what has happened in River Falls, Wis., which has undertaken a new storm water management plan and revisions to its subdivision ordinance to minimize impacts on the Kinnickinnic River.

"The biggest thing is education," says Darrin Beier, city engineer for River Falls. "If we can educate the developers in the area and the public buys into it, then the developers will have to use new techniques. If the public doesn't want that to happen, it won't."

Another effort on the Kinnickinnic suggests that the public does want to preserve the river's unique features. Since its founding in 1993, the Kinnickinnic River Land Trust has provided a measure of protection to nearly 2,000 acres within the stream's watershed. Most of the group's work has focused on getting landowners to donate conservation easements, which are restrictions on a property's deed that limit future development while allowing other activities such as farming to continue.

The trust's land registry program offers a less formal arrangement under which landowners agree to follow management practices aimed at reducing negative effects on the river. The trust is also attempting to raise funds to purchase and protect sensitive lands.

"In a conservation effort, you need as many different strategies as possible," says land trust director Rick McMonagle.

Preservation strategies still might not save all 15 remaining metro trout streams. But they will ensure a healthier environment, says Annette Drewes, one of two DNR trout stream watershed coordinators for the Twin Cities region.

"We may wind up with 10 and a better understanding of how those streams work," she says. "We're still opening people's eyes to what's out there. If you don't know what you have, you're not going to value it."

Harland Hiemstra is DNR Regional Information Officer for the Twin Cities Metro Region.