Secchi Disk Program

Like a primary care physician assessing your health through multiple tests, a limnologist wDSC_0431ill compile the results of several water quality tests to determine the overall health of the lake. One standard water quality summary is the Carlson Trophic State Index Score which uses winter levels of total phosphorous (an essential nutrient for biological growth), summer concentration of chlorophyll (the dominant pigment in algae) and secchi disk depth (a measure of water clarity). Secchi Disk measurements have been used by limnologists for two centuries.

Here on Canandaigua Lake, Dr. Bruce Gilman, Dept. of Environmental Conservation and Horticulture at FLCC, has been measuring secchi disk water clarity since the 1980’s at two mid-lake stations. For the last several years, Canandaigua Lake Watershed Association volunteers have also collected weekly secchi disk data at over 16 locations around the lake. This cooperative monitoring helps us learn about the factors that affect water clarity and overall lake health.

2016 Data for Water Clarity Monitoring

The below chart illustrates current data collected from the 2016 CLWA secchi disk volunteers. Data is updated weekly. Thanks go out to our 2016 Volunteers: Dee Crofton, Gary Helming, Kevin Hefner, Scott Hill, Bruce Kennedy, Marty Lasher, Wade Sarkis, Lynn Thurston, Vickie Tucker, Bill Yust, and Steve Zumbo.



Current Lake Conditions, September 21, 2016

Watershed Program Manager Update:

A couple of weeks ago, we observed some very small and isolated concentrations of blue green algae along the shoreline of the lake.  We sent samples to SUNY ESF on September 7th, one from the most concentrated blue green algae we saw and a second sample from the open water.  We just received the toxin analysis results, and the good news is that no toxin was found in either sample.  Although this is a good sign, it doesn’t guarantee that the blue green algae won’t start producing toxins in the future. In addition, you should still avoid contact if you see a bloom, because blue green algae can still have health impacts even if it is not producing the toxin.

We have continued to monitor the shoreline over the past couple of weeks, and the blue green algae seems to be even more isolated now than before.  The Watershed Association has volunteers that regularly monitor water clarity, and they have continued to observe excellent water clarity that was above 6 meters this week.

Please contact us if you see anything suspicious on the lake or if you have any questions or observations. The lake surface is 10,500 acres and has 36 miles of shoreline so the more eyes the better!

See our quick blue green algae guide or visit the NYS DEC website and NYS DOH website for more information on blue green algae.  If you have any questions or see a suspicious bloom, please email or

Interested in Volunteering? 


Secchi Disk volunteers use their own boats to go out on the lake and take weekly recordings. Findings are reported electronically, which makes real-time response to a possible critical condition possible. The additional data gathered by volunteers helps us supply more detail to the ongoing “picture” developing of Canandaigua Lake.

For more information, contact the CLWA office at (585) 394-5030 or email us.