A California non-profit started an ambitious project beneath the surface of Lake Tahoe that concluded Tuesday: hire scuba divers to gather the litter in the top 25 ft of the lake.

Divers have now pulled out more than 25,000 pounds of debris from the 72 miles of the lake’s shoreline, working in a circle from Stateline, Nevada. As volunteer divers navigated the lake, they plucked plastic bottles, engagement rings, 1980s Nikon film cameras, entire lampposts, “no littering” signs, big pieces of broken-down boats and engine blocks, lost wallets and cordless home telephones, according to Clean Up the Lake.

The founder and executive director of the group, Colin West, said he organized a beach cleanup in 2018, when volunteers recovered 40lb of litter from the shoreline near the popular King’s Beach. He chatted with some friends who were doing an underwater cleanup and they had recovered 600lb of litter from beneath the surface. A light went off for him, West says: “How did all that litter make it under the surface of such a beautiful lake?”

His team of volunteers started doing surveys, and they found more than 50lb of trash a diver each time they went out. They later launched the 72 Mile project to clean up the lake. The divers are supported by boats and jet skis. On any given day, the non-profit organizes 10 people on the water. They have completed 189 dives in 81 days.

Lake Tahoe is more than 1,600ft deep in some parts. Pollution from algae and fine sediments have muddied the lake’s famously clear blue waters. The lake’s clarity declined 30%, from 100 ft to 64 ft, between 1968 and 1997, according to the Environmental Protection Agency. As the climate gets hotter and less rain falls, the lake may also be threatened in unique ways: its waters warmed 15 times faster recently than the average rate over the previous century.

Picking up trash will not affect these more systemic issues, but it does make people think more about the ecology of the area, the group says. The divers didn’t go deeper than 25 ft to retrieve items, though they geotagged bulkier, deeper trash for later removal.

When looking at the litter – including anchors, tires and ropes – it’s easy to feel like people are making bad decisions, West said. But the majority of debris is accidental litter that has wound up there through normal human activities.

“You might find five or six beer cans in one area,” he said. “But the sunglasses, the cellphones, the hats, the construction material – a lot of this has happened accidentally or from wind storms. No one is trying to lose a boat anchor.”

Some of the garbage will be used to create a new art installation at a nearby events center.

In the future, the project plans to expand to three other lakes, including June Lake in the Mammoth Lakes region and Fallen Leaf Lake in the Tahoe basin. Divers will also be collecting data on invasive species and algae blooms while in the water.

They also want to monitor the situation after the cleanup to determine if it has changed for the better, or if it is back to the junk. West wants to see increased litter prevention signs, trash receptacles, and education.

“We are all part of the problem – whether you are on a boat or building a house,” says West. “So we need to be part of the solution as well.”