Scuba divers who spent a year cleaning up Lake Tahoe’s 72-mile shoreline found no trace of a mythical sea creature, mobsters in cement shoes or long-lost treasure chests – but came away with something they hope will prove much more valuable.
In addition to removing almost 11,500kg of underwater litter since last May, divers and volunteers have been meticulously sorting and logging the types and GPS locations of the waste – in a first-of-its-kind effort to learn more about the source and potential harm caused by plastics and other pollutants in the storied alpine lake on the California-Nevada border.
The scheme has also taken organisers on a journey through the history, folklore and development of the lake, atop the Sierra Nevada, which holds enough water to cover all of California.
The Washoe tribe fished the turquoise-blue Tahoe for centuries before westward expansion in the mid-1800s brought railroads, timber barons and eventually Gatsby-like decadence to what became a playground for the rich and famous.
Massive lake-front estates followed for decades, including one used for the filming of The Godfather II movie.
Clean-up organisers say one of the things locals ask most is whether they have found any gangsters’ remains near the north shore – where the late crooner Frank Sinatra lost his gaming license for allegedly fraternising with organised crime bosses at his hotel-casino in the 1960s.
The recovered debris has mainly consisted of things like bottles, tyres, fishing gear and sunglasses.
But Colin West, founder of the non-profit environmental group that launched the project, Clean Up The Lake, said there have been some surprises.
Divers think they spotted shipwreck planks near Dead Man’s Point, where tribal tales tell of a Loch Ness Monster-like creature — later dubbed “Tahoe Tessie″— living beneath Cave Rock.
They have also turned up a few “No Littering” signs, engine blocks, lamp posts, a diamond ring and “those funny, fake plastic owls that sit on boats to scare off birds,” Mr West said.
“It’s shocking to see how much trash has accumulated under what appears to be such a pristine lake,” said Matt Levitt, founder and CEO of Tahoe Blue Vodka, which has contributed 100,000 dollars (£82,000) to the clean-up.
“It is our economic engine,” Mr Levitt said.
And while most contributors and volunteers were motivated primarily to help beautify the lake, it is what happens once the litter is piled ashore that excites scientists.
Shoreline clean-ups have occurred across the nation for years, from Arizona to the Great Lakes, Pennsylvania and Florida.
But that litter goes into recycle bins and garbage bags for disposal.
Each piece from 189 separate Tahoe dives to depths of 25 feet was charted by GPS and meticulously divided into categories including plastic, metal and cloth.
Plastics are key because international research increasingly shows some types can break down into smaller pieces known as microplastics.
Scientists are still studying the extent and human harm from the tiny bits.
Zoe Harrold, a biochemist, led scientists at the Desert Research Institute in Reno that first documented microplastics in Tahoe in 2019.
She was the lead author of Clean Up The Lake’s 2021 report on a six-mile pilot project.
“If left in place, the ongoing degradation of submerged litter, particularly plastic and rubber, will continue to slowly release microplastics and leachates into Lake Tahoe’s azure waters,” Ms Harrold wrote.
The clean-up comes half a century after scientists started measuring Tahoe’s waning clarity as the basin began to experience explosive growth.
Most credit, or blame, completion of the interstate system for the 1960 Winter Olympics near Tahoe City.
The first to be televised, it introduced the world to the lake surrounded by snow-covered peaks.
Peak days now approach 300,000.
“The majority of what we’re pulling out is a result of basically just the human impact of recreating, living and building a community here in the Lake Tahoe region,” Mr West said.
His group plans dives this year at other Sierra lakes, including June Lake east of Yosemite National Park, and will expand future Tahoe searches to deeper depths.
The non-profit Tahoe Fund, which also helped raise 100,000 dollars for the clean-up effort, is commissioning artists to create a sculpture made from Tahoe’s rubbish at an events centre being built in Stateline, on the lake’s south shore.
“Our hope is that it will inspire greater environmental stewardship and remind those who love Lake Tahoe that it’s up to all of us to take care of it,” Tahoe Fund CEO Amy Berry said.