RENO, Nevada — Lake Tahoe's clarity improved again in 2014, and the drought was a factor why, researchers said.
The average clarity last year was 77.8 feet, up 7.5 feet from the previous year, reported the Tahoe Environmental Research Center of the University of California, Davis.
It represents the most year-to-year improvement in more than a decade and is part of a long-term trend showing improvement in the lake's clarity.
Researchers attribute last year's improvement to the four-year drought and an ongoing environmental restoration project aimed at controlling erosion and runoff and restoring wetlands in the Tahoe Basin. Light rain and snow led to less clarity-stealing sediment and other pollutants being washed into Tahoe. Warmer temperatures limited the mixing of lake waters in the winter to further increase clarity.
"While these latest data are very reassuring, they should not be interpreted as victory in our joint restoration efforts," said Geoffrey Schadlow, director of the research center. "Complete restoration is still decades away and some of the greatest challenges still lie ahead of us."
"We are enduring drier and warmer conditions than we have ever encountered, and the restoration consequences of that are still far from understood," he added.
The clarity was based on the average of 28 readings taken during 2014 and represents the level at which a white disc lowered from a boat vanishes from view. The deepest level was 93.5 feet in July, and the shallowest was 57.4 feet in September.
Measurements have been taken since 1968, when the clarity was 102.4 feet. A coalition of groups and governmental agencies now is trying to reach a goal of 97.4 feet set by federal and state regulators.
For the most part, readings have steadily climbed since the clarity was recorded at 64.1 feet in 1997.