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aerial image of Lake Superior showing turbid waters near Duluth

A View From the Big Lake

Mighty Lake Superior's coastal waters are actually mighty vulnerable.

By John Myers

Nearly three miles out from the Duluth Aerial Lift Bridge, the view from Lake Superior is still pretty good. Clean, clear, and mostly unspoiled, the lake seems too enormous to be affected by anything back on shore. But as passengers aboard the L.L. Smith Jr. would learn on a warm July evening cruise, the big lake has a sensitive side, especially close to shore.

And what happens on shore, we learn on the boat trip, matters to the lake. Even out here, where the water meets the sky and the lake keeps going.

Known for its stunning depths and sheer size -- the world's largest freshwater lake by surface area -- Lake Superior has a tiny portion of coastal waters that hold incredible diversity of living things. Near shore in waters less than 100 feet deep, everything from zooplankton and phytoplankton to herring and lake trout, spend critical periods of their lives.

This is also the part of the lake where people fish, kayak, and wade, and where many people who live near the lake, including those in Duluth, get their drinking water.

Online Extras:

 Ten ways you can protect Lake Superior

These coastal waters comprise only 4 percent of the lake's area and, lake advocates say, this area is most at risk from human activities on land. During the past 150 years, urban and rural development, logging, mining, and roadbuilding have removed trees, natural vegetation, and wetlands in the Lake Superior watershed -- a 49,300-square-mile area where wetlands and rivers drain into the lake. Those actions have increased runoff, sedimentation, chemical pollution, and habitat damage in streams that eventually run into Lake Superior.

"We are changing the way water moves across the landscape," said Jesse Schomberg, coastal communities educator for Minnesota Sea Grant. "Everything's moving faster to the lake."

So far, the big lake has been able to hold its own. But researchers and ecologists fear problems troubling many local streams may also plague near-shore areas of the lake. One Sea Grant study traced clay and silt that gushes from the Nemadji River, which flows from Minnesota's Carlton County through Wisconsin and into Lake Superior. Based on accounts of early explorers and American Indians, researchers believe the Nemadji once ran mostly clear. But logging and land clearing for farms started in the late 1800s and robbed the landscape of wetlands and forest cover, exposing clay soils on steep slopes to erosion and increasing the influx of runoff water from rain and snowmelt. Now, after heavy rains, the Nemadji looks like chocolate milk spilling into Superior's blue waters.

The study found the underwater plume of Nemadji sediment in Lake Superior is slowly spreading toward the North Shore. Each year an estimated 129,000 tons of Nemadji clay and silt flow into the lake.

"What if that fine sediment ends up covering up gravel in the lake that's used for spawning? We don't know yet," Schomberg said. "But the fish probably don't want to find out."

Three-Hour Cruise

The 60-foot Smith has about 25 passengers on this View From the Lake tour that brings people out on the lake to better understand how their actions on land might change these waters. Anyone is welcome, but folks who live in the Lake Superior watershed, especially local government officials, are the target audience. Since 2004, more than 1,200 people have taken the tour, which is operated by University of Minnesota Sea Grant and University of Wisconsin Extension, and partially funded by the Department of Natural Resources Minnesota's Lake Superior Coastal Program.

"We've focused on town board supervisors, planning and zoning officials, city councilors, county supervisors -- the people who decide the rules for what happens on the land," said Mindy Granley, DNR coastal nonpoint pollution specialist.

"You see things from out here, looking back, that you'd probably drive by on land and not realize, like how much of the downtown [of Duluth] is totally covered with concrete and pavement. And how little space there is for any [rainfall] to soak in," said Sue O'Halloran, University of Wisconsin Extension water resources specialist.

From the water, the land looks more crowded, the hills steeper. The city and North Shore seem to spill right down into the lake.

Runaway Water

Many passengers are surprised to hear that industries are no longer the major source of lake pollution. Paper mills, mines, and municipal sewage plants have gradually been regulated to reduce pollution since the 1970s. And some waterways have responded. The lower St. Louis River, for example, is now a trophy fishery for walleye, smallmouth bass, and muskie, thanks partly to construction of an effective wastewater treatment plant in the 1970s.

But until recently, little has been done to stop nonpoint-source pollution from the everyday activities of people who live near and visit the lake.

Boat-tour instructors report that on natural landscapes, with intact forests and wetlands, only about 10 percent of a rainfall runs off into streams. The rest percolates through soil and wetlands and into groundwater. However, in an average residential neighborhood -- where buildings, roads, sidewalks, driveways, and parking lots cover about 40 percent of the land -- runoff triples to a whopping 30 percent of rainfall. At that point, runoff degrades streams with loads of road salt and silt. Stream water temperatures warm, and erosion begins to change the stream's course.

"Whatever you're sending down the street and storm drain is coming right out here into the lake," said Amy Eliot, a watershed educator working with the University of Wisconsin-Superior.

Minnesota's Coastal Program

Minnesota's Lake Superior Coastal Program, run by DNR Waters, is a federal-state partnership to "preserve, protect and, where possible, restore or enhance coastal resources." The program helps provide places for Minnesotans to live, work, and play along the greatest of the Great Lakes. "Our mission is really focused on balancing the economic and social needs of local communities with the need to protect and restore the health of Lake Superior," said Pat Collins, program director. Based in Two Harbors, the coastal program works with 31 local units of government along 189 miles of shoreline on Minnesota's share of Lake Superior and the lower St. Louis River. Since its inception in 1999, the program has funneled more than $6 million in federal grants to North Shore communities for projects to protect the lake and help people enjoy it. More information.

Onboard Exercise

When the Smith reaches water 80 feet deep, nearly three miles out from Duluth's harbor and a couple miles off the North Shore, the engines stop and instructors set up "classrooms" on deck.

At the stern, half the entourage gathers for a role-playing game of Watershed Management. As they barter over land-use rules, players represent loggers, farmers, city planners, and housing developers. Bobbing on the lake, not far from the Lester and Amity rivers, they work out compromises to protect a mythical stream from becoming clogged with silt and too muddy for trout.

"If there's one lesson we try to instill on the boat, it's that what you do (on land) matters. What you do on your own property, in your community, eventually affects Lake Superior," Schomberg said.

In the real world back on shore, communities near Lake Superior are beginning to take better care of the streams that flow into the greatest of Great Lakes. At Hidden Creek Preserve in Hermantown, Schomberg noted, housing developers are leaving more natural areas and clustering houses on smaller lots farther from streams. And before a few stores moved forward with expansion plans on their small lots in Hermantown, they built underground stormwater retention vaults to hold and cool rainwater runoff before it enters Miller Creek, an impaired trout stream and Lake Superior tributary.

In Duluth Township, zoning officials recently adopted a 300-foot setback for new construction along trout streams. That stricter setback helps keep a buffer of vegetation to absorb, slow, and cool runoff before it gets to the waterway. Throughout the Duluth area, The Regional Stormwater Protection Team -- comprised of more than 20 public agencies and local governments -- are encouraging the construction of new parking lots with permeable surfaces that allow rainwater to soak in. The University of Minnesota-Duluth has built rain gardens to slow and filter runoff.

Over a weekend last April, Duluth residents, ecologists, designers, developers, landowners, and city officials met for long hours to decide how to plot the future of just one chunk of undeveloped land along Amity Creek, one of the city's 42 streams that flow into the harbor or lake.

"We can't stop our communities around the lake from growing," O'Halloran said, "but we can try to provide people with the information they need to make informed choices on how they grow. Nearly everything we do in our communities is going to have some impact out here."

Clear Vision

When participants on the Smith drop Secchi disks on ropes into the lake near Duluth to measure water clarity, they can see the white disks 25, 30, or even 35 feet below the surface before they disappear. That's considered extraordinary clarity -- more than double most of Minnesota's lakes. Off Grand Marais last summer, the Smith crew had to add rope to the Secchi disk because it remained visible to a whopping 60 feet deep.

Meanwhile, inside the Smith's lab room, some participants use microscopes to examine water and sediment samples. Although Superior is the coldest and most infertile of the Great Lakes, it is far from sterile.

"There's a little orange guy in here, but he's very small," Kate Campbell, a passenger from Duluth, calls out while peering into a petri dish of lake water. Plankton, amphipods, insect larvae, midge larvae, and aquatic worms form the base of the big lake's food chain. They show the lake ecosystem is working despite threats.

But it might not stay that way. A tiny native shrimp, or amphipod, that's critical food for many small fish is rapidly disappearing from Lake Michigan. National Oceanic and Atmospheric Administration scientists are blaming nonnative invasive quagga mussels. The U.S. Environmental Protection Agency has confirmed that quagga mussels are also in the Duluth-Superior harbor.

Global View, Local Action

Instructors aboard the Smith acknowledge that Lake Superior also faces broader issues that impact the entire lake and will require global solutions. Mercury pollution that falls from the sky, for example, can come not only from nearby coal-burning power plants, but from coal power plants as far away as Asia. Toxaphene -- an insecticide that's banned in the United States but still used in other countries -- is also falling from the sky after traveling the globe as a gas. Toxaphene persists in our environment from its past usage in our country, along with other "legacy" pollutants such as PCBs and DDT.

Of the 185 invasive species now found in the Great Lakes, more than half are in Lake Superior. The latest invasive species threat is a fish-killing virus from saltwater, viral hemorrhagic septicemia. VHS is as close as Lake Michigan and has killed large numbers of native fish in the lower Great Lakes during the past three summers.

And then there's climate change: A University of Minnesota-Duluth study released in March found the lake's water temperatures have been warming in recent decades at about double the rate of local air temperatures, which means Superior is particularly sensitive to a warming climate. No one knows the impact that warming will have on native species such as lake trout, herring, and sturgeon. Scientists have tracked an increase in the amount and severity of heavy rainfalls -- more gully washer storms and fewer daylong soakers, which could increase runoff and erosion problems.

Despite the varied threats facing Lake Superior, passengers leave their View From the Lake tour with the urge to act. In follow-up interviews, nearly half of them report taking action based on what they learned.

Chuck Campbell, a town board supervisor in Lakewood, said the July evening boat trip helped him better understand the issues he grapples with as his rural community grows. "We're the first suburb out from Duluth, where people want to move for the rural lifestyle. We have to decide on setbacks and variances and [building] requests all the time," he said. "Most of the good land has been settled now, and the property where people want to build is the more marginal land -- near wetlands and near streams or on steeper grades. How and where we deal with that is going to affect the lake in a big way."

Boat trip information. Or call 218-726-8106.

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