Tahoe: State of the Lake Report 2013

“Lake Tahoe’s average clarity in 2012 increased by 6.4 feet over the previous year, however, long-term trends show that climate change is impacting the Lake Tahoe Basin.”  Evidence of these effects include the highest surface temperature ever recorded; a reduction in snowfall as a percentage of total precipitation; and a net loss in lake level in 2012.  Since 1968 researchers at the University of California Davis have been monitoring water clarity, physics, chemistry and biology.  Their report “Tahoe: State of the Lake Report 2013” states that “the annual average clarity is 75.3 feet and is within 3 feet of the interim clarity target of 78 feet.  The data shown reveal a unique record of trends and patterns – the result of natural forces and human actions that operate at time scales ranging from minutes to decades.”  The improvement in water clarity can be attributed to the following: reduced precipitation resulting in fewer pollutants flowing into the lake, the absence of deep water mixing and reduced numbers of tiny Cyclotella algae.  When the long-term measurement program began in 1968, average annual clarity was 102.4 feet.  To read the press release from U C Davis, go to the Sierra Sun website or for the complete report, check out the University of California website.