Lake Tahoe is a Northern California gem, boasting some of the clearest and most beautiful water in the world. But now that water is not as clear as it once was.
Researchers from the UC Davis Tahoe Environmental Research Center (TERC) announced that Lake Tahoe’s water clarity declined 9.5 feet in 2017, around a 15 percent change for the lake that saw a five-year average lake clarity of approximately 70 feet.
The numbers follow a 3.9-foot decrease in average annual clarity in 2016. That is a decrease in 13.4 feet over the past two years. The previous lowest recorded average of 64.1 feet was recorded in 1997. Today, water clarity sits at an all-time low of 59.7 feet.
Although these numbers can be startling, researchers say this is just s freak confluence of negative causation, rather than the new normal. TERC Director Geoffrey Schladow, a professor of engineering at UC Davis, explained the low clarity numbers.
“The combination of arguably the most extreme drought period ending with the most extreme precipitation year produced the low clarity values seen,” Schladow said in a statement. “Measurements for 2018 have already shown a large improvement that are more in line with the long-term trend.”
The extended drought of 2015-16 followed by extreme precipitation in 2017 washed approximately five years of sediment into the lake. The lake’s clarity has already improved in 2018 and officials are working to keep sediment out of the water with a goal of eventually reaching lake clarity of 100 feet.