Lake Tahoe's famed water gets clearer after all-time low

RENO, Nev. (AP) — The clarity of Lake Tahoe's cobalt blue water improved last year from its worst level in a half-century after weather and runoff returned to more normal conditions at the alpine lake straddling the California-Nevada line.

A dinner plate-sized disc used to measure clarity was visible at an average depth of 70.9 feet (21.6 meters) in 2018, scientists at the University of California, Davis, Tahoe Environmental Research Center said Thursday.

That's an improvement of 10.5 feet (3.2 meters) from 2017 when a winter with unusually heavy snow followed years of drought, sending sediment into the scenic lake known for its pine tree-lined beaches and ski resorts. The research center typically releases its annual clarity findings in the spring after analyzing the data it gathers each month in the previous year.

Scientists hope efforts to combat threats to clarity posed by development and climate change will eventually return Lake Tahoe to its historical clear depth of 100 feet (30.5 meters).

Dozens of public and private partners have been working to reduce stormwater pollution from roads and urban areas and restore streams and floodplains to reduce the amount of fine particles and nutrients that can cloud the lake, research center director Geoffrey Schladow said.

Clarity can swing widely day to day and year to year due to weather conditions and the flow from streams that can accelerate or slow algae growth and erosion that sends sediment particles into the water, he said.

"In 2018, Lake Tahoe's clarity regained the expected seasonal patterns that were disrupted by the extreme conditions of the previous year," Schladow said.

Scientists took 26 individual depth readings in 2018, including one in March that exceeded 100 feet (30.5 meters) of clarity. The worst...