Muck move spurs rebirth of polluted Duluth harbor site

Call it "environmental muck."

Mud that settled over the years in the backwaters of the St. Louis River, choking off what had been an open-water channel and prime fish habitat behind Tallas Island near Duluth, is being vacuumed up and piped two miles away to be sprayed out at the Stryker Bay Superfund site in the Duluth harbor.

State pollution regulators say the muck - filled with seeds, bugs and invertebrates - should jump-start a new, healthy wetland ecosystem in what had been one of Minnesota's most polluted sites.

"It's a win-win situation at both ends," Susan Johnson, project manager for the Minnesota Pollution Control Agency, told the Duluth News Tribune. "We are getting all this great media that has all the critters and seeds already in it to start a healthy wetland in the bay. ... And it's reopening what had been an open-water channel until it filled in with erosion."

About 75,000 cubic yards of muck will be sprayed about 6 inches deep across much of the Superfund area in the fifth and final year of major work to dredge and cap massive contamination left by a century of industrial waste.

Stryker Bay and nearby Slips 6 and 7 were heavily polluted from the late 1800s into the 1960s. That part of the Duluth harbor was once ringed with tar and coke plants, heavy industry and slaughterhouses. Coal tar deposits were 13 feet thick under the water in some places.

MPCA officials have been working on the cleanup since 1979, and the site has been on the federal Superfund list since 1983. It's one of the four largest Superfund projects in Minnesota history. The work will end this fall at a cost of more than $62 million.

The Tallas Island area is about four miles upstream from Lake Superior and roughly two miles upstream from Stryker Bay. It's a bastion of wildlife surrounded by development, home to herons, beaver, deer and bears. The new channel there will include some deep holes for fish habitat.

"They'll be in there as soon as we take the (sediment) curtains down - both the fish and the fishermen," joked Tom McGann, project manager for aether dbs, the contractor heading the cleanup project.

Some of the Tallas muck was dredged last winter and trucked to the Superfund site, and those areas already have turned a lush green. So far, wildlife experts say the mix of cattails and grasses looks good and is mostly free from invasive species.

The cost of cleaning up Stryker Bay Slips 6 and 7 will surpass $62 million by year's end.

Slip 6 has been filled in and mostly sealed off from the river, entombing the contaminated sediment. Slip 7 has been partially capped, and a natural stream still flows through the site. A man-made sand beach is being planted with dune grass in hopes of attracting rare shorebirds. Some of Slip 7 has been left deep enough for industrial barge use.

Around much of the site, a buffer zone of trees, grass and shrubs will be left and hiking trails are envisioned for the area, though that's not part of the cleanup project itself.

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Information from: Duluth News Tribune

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