Home Natural cosmetics Lake Tahoe drops to alarming levels

Lake Tahoe drops to alarming levels

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This week, a historically dry spell in California will occur at Lake Tahoe, where the water level is expected to drop below the natural edge of the basin. It is at this point that the lake empties into its only flow, the Truckee River.

It’s not a crisis, say researchers and environmentalists, but it marks another extreme turning point for Tahoe amid historic drought, wildfires and erratic weather conditions, all linked to climate change and becoming aspects of it. most important of the alpine environment.

“Going below the natural edge won’t change much in the lake itself. But there is very little positive about the low levels of the lakes once they descend below the rim, ”said Geoffrey Schladow, director of the Tahoe Environmental Research Center at UC Davis.

Tahoe’s natural rim sits at 6,223 feet above sea level. A dam on the Truckee River allows the lake to fill about 6 feet higher, to 6,229.1 feet, according to the US Geological Survey.

The water level has fallen below the rim four times since 2004, most recently in the fall of 2016, the highlight of California’s historic drought. However, this tense period was followed by a record winter for precipitation in the Tahoe region in 2017, which replenished the Sierra’s snowpack and brought the lake to its highest peaks in decades.

The water level has mostly dropped since the summer of 2019, when it was near the lake limit, and is currently about 1 ½ inch above the edge. The plunge is mainly due to the meager snowpack in the mountains surrounding the lake as well as evaporation, which sucks about 3 feet deep from the lake each year, according to Tahoe Water Authorities.

This time around, researchers and environmental nonprofits monitoring the lake are not optimistic that the water will return as quickly as in 2017.

“If we have another dry winter, it could become a bigger concern,” Schladow said.

Tahoe has receded steadily throughout the year, and the plunging water level is changing the character of its shore.

The Truckee River, Tahoe’s only outlet, slowed to a trickle. The private docks on the North Shore are high and dry. Boat ramps plunge directly into the bare earth. Entire coves of the east coast, popular with kayakers, have dried up. The South Shore has become a giant sandbank. Beaches in shallower areas have widened by several hundred meters, exposing parts of the lake that people aren’t used to seeing and revealing stinky deposits of decaying algae.

“You can’t get within 150 yards of the normal shore” in South Lake Tahoe, said Kelsey Weist, owner of Clearly Tahoe, which runs glass-bottom kayak tours around the lake.

So far, most of the impact has been felt by the boating and tourism companies who have had to get creative to get their customers on the water. Marinas dredge deeper to maintain access to boaters.

Weist, who runs tours all year round, has adapted by revamping his itineraries. A popular event that drove paddlers along the Upper Truckee Marsh – usually a great spot for wildlife viewing – had to be called off in early July, Weist said.

“We don’t expect this to be the last time we have this challenge,” Weist said. “With global warming, we know we will never be able to anticipate a normal season again.”

The lake bed is on display at Kings Beach on Sunday - the water level is so low at Lake Tahoe it is in danger of stagnating.

The lake bed is on display at Kings Beach on Sunday – the water level is so low at Lake Tahoe it is in danger of stagnating.

Max Whittaker / Chronicle of San Francisco

Upper Truckee Marsh marks the spot where Tahoe’s largest influx, the Upper Truckee, reaches the lake. It is a key habitat for kokanee salmon, which would normally move up the river at this time of year in the hundreds to spawn. But on Friday, in the afternoon sun, Jesse Patterson looked into the water and only counted two. Nearby, piles of dead algae have decomposed on the beach.

“It’s incredibly low,” said Patterson, director of strategy for the League to Save Lake Tahoe, a nonprofit conservation and cleanup organization. “The concern is what it looks like if it continues for years in a row. “

Beyond cosmetics, there is the potential for environmental effects.

Climate change has warmed the lake, which in turn has given rise to algae blooms that have, in recent years, tarnished its famous clarity. The more the lake warms up, the less likely it is to “turn over”, a phenomenon of periodic mixing that helps to keep the aquatic ecosystem balanced and healthy.

If water levels were to stay below the rim, Tahoe could become “terminal,” a designation of bodies of water with no flow. These lakes are known for their high salinity and lack of aquatic life – the Salton Sea and Mono Lake are two examples in California.

Another possible change in Tahoe if water levels remain low is the emergence of the shallow sill at the mouth of Emerald Bay, which could separate the bay from the rest of the lake. Such separation “could occur at the mouths of many streams, cutting off spawning access for kokanee salmon next fall,” according to an email update from UC’s Tahoe Environmental Research Center. Davis.

But there is cause for optimism: snow has already fallen in Tahoe at least twice this month; a quarter of an inch fell in parts of the lake on Monday.

“It is likely that winter will arrive in the next few months and that the lake level will rise above the natural edge soon after,” according to the Tahoe Environmental Research Center. However, in its email, the center said things could get worse.

“There is no limit to the number of years of drought and the drop in water level. The most recent estimates suggest persistent drought conditions.

What worries the defenders of the lakes is the global toll of more frequent extreme events – historic drought and weak snowpack, high temperatures, smoky skies, the Caldor fire.

“This makes us wonder, is the lake at a tipping point?” said Darcie Goodman Collins, CEO of the League to Save Lake Tahoe. “There is a lot we can do to help the lake withstand climate change – restore wetlands and natural waterways, eliminate invasive species. But it is valid to ask these questions because it happens so quickly. “


Gregory Thomas is the editor of the lifestyle & outdoor column of the Chronicle. Email: [email protected] Twitter: @GregRThomas



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