Lake Tahoe, a popular alpine resort in the Sierra Nevada mountains, experienced its 14th driest year on record in 2007, but clarity in the picturesque lake was better than in 2006.

Researchers at the University of California’s Davis campus, (UC Davis) said the historical rate of decline in clarity seems to have slowed between 2001 and 2007, although they warned the finding was “tentative”.

In 2007, the famously cobalt-blue lake was clear to an average depth of 70.1 feet, compared to 67.7 feet in 2006.

The university’s second annual Tahoe: State of the Lake Report summarises tens of thousands of scientific observations on weather, water conditions and aquatic life.

Last year’s inaugural health check confirmed the climate in the Lake Tahoe Basin is warming up, which could result in more rain and less snow, and earlier snowmelt.

This year’s report showed ten of the 12 months in 2007 were drier than average and rainfall was 19.7 inches – two-thirds of the normal levels.

Geoffrey Schladow, director of the UC Davis Tahoe Environmental Research Center, said: “The data in the Tahoe: State of the Lake Report reveals a unique record of trends and patterns – the result of natural forces and human actions that operate over time scales ranging from days to decades.”

He added: “These patterns tell us that Lake Tahoe is a complex ecosystem, and it behaves in ways we don’t always expect.”

The report also said it is too early to assess how the lake may have been affected by pollution from fires in the nearby Angora Lakes area last summer.

It is feared that streams and urban run-off from the burn area could have washed fine particles and excess nutrients into the lake.

Kate Martin

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