Best clarity in Lake Tahoe since the 1980s, thanks to the storms
Recent storms have improved the clarity of Lake Tahoe in the last five months of 2022, now being the clearest it has ever been since the 1980s.
According to the Lake Tahoe Clarity Report 2022 that was released by the UC Davis Tahoe Environmental Research Center (TERC), this is partly due to a resurgence of the lake's native zooplankton.
The average annual clarity in 2022 was 71.7 feet, compared to 61 feet the year before. Specifically between August to December, the average clarity stood at 80.6 feet, which coincided with the highest numbers of the zooplankton Daphnia and Bosmina. These zooplankton are specialized to consume particles in the size range that impact clarity.
Geoffrey Schladow, Director of the UC Davis Tahoe Environmental Research Center, said, "Daphnia and Bosmina largely disappeared from the lake after they were grazed down following the introduction of the Mysis shrimp in the 1960s. In late 2021, the Mysis population unexpectedly crashed, and it took 12 months for the Daphnia and Bosmina to build up their numbers and start their natural cleansing."
Other factors that affect clarity include the magnitude of the runoff, the warming of the lake surface and the depth to which the lake mixes in the previous winter.
Researchers expect the clarity improvement to continue through 2023. In the meantime, TERC scientists are monitoring zooplankton communities through donor funding and are also working with local fishing guides to monitor changes to fish.
Both the states of California and Nevada are working to bring the lake clarity back to its record depth of 97.4 feet.
The clarity report is funded by the Tahoe Regional Planning Agency.
