UC Davis researchers noted several bright spots in their annual Lake Tahoe health report, issued today: The 2007 Angora Fire had no significant impact on lake clarity; a small test of a method to kill invasive clams worked; the pollutant phosphorus was at its lowest level in 29 years; and free-floating algae in the lake have generally remained constant since 1996.

Earlier this month, the UC Davis Tahoe Environmental Research Center announced that lake clarity held relatively steady in 2009. It was noted that the rate of decline in Lake Tahoe’s clarity since 2000 was less that that seen in past decades.

"Overall, we remain cautiously optimistic," said John Reuter, associate director of the UC Davis Tahoe Environmental Research Center.

The "Tahoe: State of the Lake Report" is intended to give the public a better understanding of the changes occurring in Lake Tahoe on a year-to-year basis and to place current conditions within a historical perspective. It summarizes tens of thousands of scientific observations of lake weather, water conditions and aquatic life made since 1900.

“This report is an impartial, annual accounting of many key variables of lake change,” said Geoff Schladow, director of the UC Davis Tahoe Environmental Research Center. “It helps us all recognize the differences between natural variability and long-term change, and how our efforts toward the restoration of Lake Tahoe are progressing.”

Reuter emphasized that the lake is not out of the woods, "but it does have the ability to improve, provided that pollution control is achieved."

The new report also shows these 2009 events: Potentially disastrous invasive quagga mussels were found on 10 boats inspected by Tahoe management agencies as they headed for the lake. More precipitation fell as rain and less as snow. Algae attached to rocks and docks increased along the northeast shoreline. The amount of water-clouding particles and nutrients reaching the lake by west-side streams increased as precipitation rose from previous years. Lake levels fell below the natural rim of the lake, causing water to stop flowing into the Truckee River.

The full 69-page report is online at http://terc.ucdavis.edu.