Interstate island is disappearing into the St. Louis River estuary, threatening one of only two tern colonies remaining on Lake Superior, but a two-year effort to raise the tiny island and help the terns is set to begin.
The $1.4 million project will use sand from on-land sources and dredged from nearby shipping lanes in the Duluth-Superior harbor to raise the island that has succumbed to rising water levels since 2015. Lake Superior is up 14 inches from normal July levels, and that mass of water pushes into the harbor and estuary, inundating the island and wreaking havoc — much as it has along the South Shore, Park Point and along Duluth's waterfront — especially during high winds.
Already crammed onto the five-acre and shrinking island with more than 30,000 adult and young ring-billed gulls, the rising water is squeezing about 150 nesting pairs of terns out of their last suitable habitat in the region. The only other nesting colony of so-called common terns on Lake Superior is in Ashland.
RELATED: The gulls of "Bird Island"
The gulls have been eating both tern eggs and newly hatched tern chicks.
“The number of terns is down this summer from recent years because of predation by the gulls," said Fred Strand, a retired Wisconsin DNR wildlife manager who has been working to restore the island’s terns for years. “The island is noticeably smaller than it was just a couple of years ago … there’s now standing water in the interior of the island; we've never seen that before … and that’s pushing the gulls into the tern area.”
Martha Minchak, Minnesota DNR wildlife manager in Duluth, said Interstate Island State Wildlife Management Area "is eroding more than we've ever seen it before. Every time there's wave action, we lose more of it."
The island sits along the main shipping channels in the Duluth-Superior harbor right on the Minnesota-Wisconsin boundary line, just upstream of the Blatnik Bridge.
Money for the project is coming from Minnesota conservation sales tax funds and from federal wildlife and Great Lakes restoration grants. The Minnesota Land Trust and Minnesota Department of Natural Resources are heading the effort. They hope to get permits, hire a contractor and bring 13,000 cubic yards of sand to the island by autumn, starting as soon as the terns leave to go south.
“That should be enough material to offer some help for next year’s terns. Then we’ll do an even bigger project in 2020," said Melissa Sjolund, who coordinates St. Louis River restoration efforts for the Minnesota DNR. “We’ll also bring in some small gravel that the terns like to use for their nests.”
Organizers hope to raise the center of the island where terns nest amid an elaborate system of wires and fencing erected to keep gulls out. The effort, underway for years and first reported in the News Tribune in 2016, is a joint project by Wisconsin and Minnesota DNR wildlife officials and the Natural Resources Research Institute at UMD. Until high water came, the effort was working to bolster tern numbers. Banding studies show terns hatched on the island are surviving and eventually nesting on their own.
But it’s been getting harder to keep the gulls and terns apart as the island shrinks, Sjolund said.
“There’s less real estate to share," she said.
Sand will be tested to make sure it’s not contaminated. Sand from shipping channels, dredged deep to allow big boats to navigate the harbor, usually is clean because it fills in quickly, swept downstream by the river. Material dredged from boat slips and bays that aren’t flushed by currents often are contaminated with legacy pollutants.
The Interstate island project will have to compete with several others for what has become valuable sand dredged for the harbor. Dredge material was recently used to fill in parts of the Duluth harbor near the Western Lake Superior Sanitary District sewage plant to restore shallow-water habitat for fish and wildlife. Dredged material also is being used to build dry-land shore area for endangered piping plovers on the bay side of Wisconsin Point.
The Interstate island project is part of part of the massive Great Lake Restoration Initiative to dredge or cap legacy pollution, restore fish and wildlife habitat and thwart invasive species across all the Great Lakes. It's one of many restoration projects that’s either already completed, underway or planned in the Twin Ports as officials seek to remove the St. Louis River estuary-Twin Ports harbor from the infamous list of toxic, degraded hotspots across the Great Lakes called Areas of Concern.
Interstate island is a protected bird sanctuary and is closed to the public from March 1 to Aug. 30 each year, not that you’d want to go there considering the shower of gull guano you’d get.
Perch Lake suffocating
The state portion of the Intestate Island state funding was included in a $3.77 million package approved in May by the Minnesota Legislature with all the money aimed at the ongoing St. Louis River restoration effort. Most of that will go toward a massive, $6.75 million effort to restore life to Perch Lake in western Duluth. The feds are also kicking in $3.5 million for Perch Lake.
The small lake, located along Minnesota Highway 23 between Duluth’s Gary-New Duluth and Fond du Lac neighborhoods, looks like an isolated pond. It’s only connection now to the nearby St. Louis River is a four-foot culvert.
But what is now called a lake was once a backwater bend of the river, flushed during floods and during high water and likely prime nesting and growth habitat for fish and wildlife. Construction of the highway isolated Perch Lake, which is filling with muck, Sjolund said, low in oxygen and mostly fishless.
The U.S. Army Corps of Engineers is figuring out the best way to bring river water into Perch Lake, and then back out again, Sjolund added.
“We really don’t know yet what the best alternative is, whether we need larger connections or a full-scale bridge over a larger opening, or what," she said, noting the Minnesota Department of Transportation is involved in the effort.
Actual construction of the Perch Lake project likely won’t begin until 2021, Sjolund noted.
Interstate island funding
NOAA Coastal Program: $5,200
Minnesota Outdoor Heritage Fund: $487,000 ($400,000 this year, $87,000 from a previous year)
USF&WS Great Lakes Fish and Wildlife Restoration Act: $145,000
USF&WS Coastal Program: $200,000
EPA Great Lakes Restoration Initiative: $834,650
Perch Lake Funding
Minnesota Outdoor Heritage Fund: $3,242,000 (multiple appropriations)
EPA Great Lakes Restoration Initiative: $3,512,700