TERC Boat Captain and participants observe the Secchi disc as it is lowered into the water to find the clarity reading for the day.

Water Clarity

Lake Tahoe is known around the world for its famed water clarity, eliciting awe from millions of visitors each year. UC Davis researchers have been monitoring the changes in lake clarity for the past 50 years using a Secchi disk (the white dinner plate). From the late 1960's through the turn of the century, there was a decline in clarity brought about by increased algae growth and the presence of very fine particles. Over the past decade we have seen the rate of clarity decline ease with winter clarity actually improving. Using technology beyond the dinner plate, researchers continue to refine their understanding of lake physics and ecology to determine the cause of annual clarity change, enabling management agencies to focus on the most pressing issues effecting Tahoe's clarity.

Click here to read about the most recent Secchi Information

Click here for a table of TERC's Secchi Data since 1968

2017 Secchi Data

2017 Secchi Data