In Mille Lacs, divers go deep to uncover lake’s trash problem

Thousands of people flock to Mille Lacs Lake in central Minnesota every year to fish, boat and swim. But they leave behind a unsightly problem: trash that washes up on shore or sinks to the lake’s bottom.

Scuba divers from Clean Up The Lake, a nonprofit group based in Lake Tahoe, Nev., recently spent two weeks taking a closer look at Mille Lacs’ submerged litter to better understand where it’s coming from, and how to prevent it.

“It’s been an issue that’s really been out of sight and out of mind for so many people,” said Colin West, a filmmaker and former wine sommelier who founded the group, and serves as its executive director.

West said there’s been much consternation over the global problem of oceanic garbage, but the same attention hasn’t been paid to freshwater lakes, which are often sources of drinking water.

Clean Up The Lake has worked mainly on lakes in the western U.S. It gained attention in 2022 for removing 25,000 pounds of trash from Lake Tahoe. 

This was the team’s first Minnesota project, but West hopes to return, possibly to help train other groups to organize cleanups on more lakes.

A trashy problem

On Mille Lacs, Minnesota’s second-largest lake and a premier fishing destination, concern has been growing over garbage left behind by ice anglers and other lake users.

The popularity of ice fishing has soared in recent years, while better equipment and wheelhouses have made it easier for anglers to stay on the ice comfortably for long periods.

Clean Up The Lake was invited to Minnesota by Ann Brucciani Lyon, vice chair of the Mille Lacs Area Community Foundation. She hoped West’s team could provide insight into how much trash lay under the lake’s surface.

“I’ve heard everything. I’ve heard, ‘We have no litter in the lake’ to ‘We have reefs packed with litter,’” Lyon said. “The only way we’ll know is if we get somebody under the water to take a look at it.”

Brucciani Lyon is also a member of the Keep It Clean Coalition, a grassroots effort to tackle the problem of litter left on the ice. It started on Lake of the Woods, and now encompasses more than 1,200 Minnesota lakes.

In 2023, the group successfully lobbied for passage of a state law making it illegal to place garbage or human waste on the ice in the winter.

“We hope that the law just pushes that awareness, and people pack out what they pack in,” Lyon said. “It’s a simple ask. If we all want to enjoy the lakes, the fisheries, the rivers, we’ve got to keep them clean.”

Searching the deep

When West’s team arrived at Mille Lacs on Sept. 16, they gathered information from locals about fishing hot spots, and looked at lake depth and wind patterns, plotting where they'd be most likely to find trash.

Using both human divers and remote-operated underwater vehicles, the team combed the lake bottom, retrieving any debris they found. They searched 15 sites, covering a wide portion of the 132,500-acre lake.

Their finds included beer cans, glass bottles, tires, cinder blocks, fishing poles, lures, anchors, cell phones and a hubcap. It’s typical evidence of human impact, divemaster Shawn Louth said.

“I think it’s the nature of recreation,” he said. “There’s going to be litter if there’s people playing outside. So it’s a natural thing that’s unfortunate, and it’s not good for the environment.”

The trash was taken to a local school, where students and volunteers helped identify and sort it into 83 different categories. That allows researchers to trace the litter back to its source, West said.

“We can say, ‘Hey, this region, you have a problem with construction debris. You need to talk to your construction companies,” he said. 

Or where they find beer cans, beach toys and sunglasses, they might conclude it’s a party spot that requires waste bins, better management or an alcohol ban, he said.

‘A much cleaner lake’

The results of the two-week study were surprising, but positive: The team found less trash than they anticipated.

“We’ve been seeing a much cleaner lake here than we thought we would,” West said.

He has a few theories about why. Mille Lacs is relatively shallow, with a lot of wind and wave action. Lightweight garbage, such as aluminum cans and plastic bags, might be swept toward shore instead of sinking, he said. 

The divers said the lake’s limited visibility, silt bottom and invasive species — including zebra mussels — sometimes made it challenging to spot trash.

“We’ve had to take out our knives and scrape off certain things to just make sure it wasn’t a rock, because there were so many mussels on it,” Louth said.

But it’s also likely that local stewardship and cleanup efforts have paid off and helped reduce litter in and around Mille Lacs, West said.

“People trying to protect the lake in their own backyard is very important, and they need to continue to do so,” he said. “Visitors need to really focus on respecting the areas that they visit, and leave it better than they found it.”

West said his team will analyze the data collected and document its findings in a detailed report, including recommendations for future efforts to manage litter on Mille Lacs. He said it also may be worthwhile to send snorkelers to clean up litter close to shore.

Brucciani Lyon said the report will help her group decide where to focus its efforts, whether on more public education, a spring cleanup or evaluating more areas of the lake.

“I know there’s a lot of interest in what those results and recommendations are,” she said.

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