DULUTH – The city is warning residents to be careful on Park Point beaches after locals found 1970s-era metal can fragments that were dumped during a recent dredging project aimed at protecting the shoreline from Lake Superior's high water levels.

The discovery comes after former leaders of Minnesota's Pollution Control Agency (MPCA) argued that depositing the dredged silt and sand on Park Point was illegal under the terms of a 1978 settlement.

A statement from the U.S. Army Corps of Engineers, which launched the dredging project last fall, said officials are "monitoring the placement site and collecting can debris as weather conditions allow."

"Corps of Engineers officials take the situation very seriously and are developing a plan to mitigate the possibility of encountering debris in dredge material in the future," the statement said.

The Army Corps dredges more than 100,000 cubic yards of silt and sand from the harbor each year to keep it open for navigation. In the fall, with permission from the MPCA, it began depositing some of that material on the lake side of Park Point between the shipping canal and S. 13th Street.

Residents of the 6-mile sand spit, also known as Minnesota Point, urged on the efforts after record-high water levels threatened the 300 homes, hotels and businesses on the skinny strip of land.

"It's really a desperate situation," Dawn Buck, president of the Park Point Community Club, said of the recent erosion.

Buck said neighbors first noticed pieces of old cans on the beach in October after one got stuck in a dog's paw. Since then, residents have collected full garbage bags of the fragments and expect to see more when snow melts in the spring.

She added that she was encouraged by the Army Corps' "ownership of this unfortunate situation" and plans to keep asking questions to figure out why this happened and how to ensure it doesn't happen again.

"We have to work together to make sure we're doing the very best thing for Lake Superior," she said, "because that's the greatest treasure we have up here."

A spokesperson for the city said staff is working with the Army Corps to post cautionary signs on the beach.

Old legal questions

High water levels in the mid-1970s prompted the Army Corps to attempt a similar dredging project, but the Minnesota Conservation Federation and the state of Wisconsin filed a lawsuit in 1976 arguing that such actions would release dangerous pollutants from Duluth's industrial giants into the Great Lake.

"This basically proves our point," said Willis Mattison, a retired ecologist who worked with the MPCA for 28 years and raised questions about the legality of the recent dredging work. "They have not sampled, analyzed and predicted the impacts of cans on the beach just like they have not sampled, analyzed and predicted other adverse impacts on the lake."

A settlement signed in 1978 said the Corps must "give good faith and reasonable consideration to the feasibility of on-land dredge material disposal areas" before putting the fill in the lake. The Corps is allowed to consider cost, environmental impact and availability of sites, "along with other relevant factors," as it decides where to put the material.

"That agreement, apparently, has been broken," said Lance Ness, president of the Conservation Federation. "We're in discussions with the Army Corps of Engineers and the Minnesota Pollution Control Agency about how to rectify the situation that's occurred."

Bill Dowell, a spokesman for the Army Corps, said the agency has not broken the terms of the settlement by carefully choosing to place the dredge material on Park Point. The Corps often exceeded environmental standards required of it during the dredging process, he added.

Lucie Amundsen, a communication specialist for the MPCA, echoed those sentiments in a statement saying the agencies went "beyond the standards of the Clean Water Act in testing this dredge material and determined there is no threat to human health or the environment."

Screens on the dredging equipment typically filter out debris, Dowell said, but the buried pieces of aluminum and other metal were just small enough to pass through the gaps.

"This is just another one of those engineering complications where you have to go: How are we going to make sure this never happens again?" he said. "That's what we're going to do."

Ness said he is optimistic the entities will find a way to clean up the beach and find an alternative site for disposing dredge spoils without going to court. He shares concerns about Park Point's crumbling shoreline but hopes to address the problem "in a more safe environmental way."

The Army Corps said it believes about 27,000 of the 49,000 cubic yards of material used to nourish that portion of the beach was dredged from the area containing the debris. In the past two years, the agency has also used material from the harbor to bolster the southern side of Park Point and Interstate Island, a small piece of land that is home to one of Minnesota's last known common tern colonies.

Dowell did not know Friday which future sites in the Twin Ports might receive dredge material, but he said local entities often help identify areas in need as the Army Corps regularly works to maintain the harbor for shipping.

Park Point has been a prime recipient of this material of late because residents have faced an abnormal amount of property damage, likely due to a combination of storms and high waters, lighthouse piers cutting off natural sediment flows and a geological phenomenon that's ever-so-slowly tipping water toward Duluth as the bottom of Lake Superior springs back from the weight of the glacier that formed it.

Buck said Park Point residents have talked with professors at the University of Minnesota Duluth about potential long-term solutions to their problems because the dredging material will eventually be wiped away by the elements.

"Right now," she added, "we're just trying to work with the city and these other partners to be the best stewards we can."

Katie Galioto • 612-673-4478