Secchi readings are an effective method of measuring water clarity. A Secchi disk is an 8-inch diameter black and white disk attached to a gauged rope. Two measurements are obtained and averaged for the final reading. The disk is first lowered into the water to record the depth at which it disappears. The rope is then lowered deeper and then raised to record the depth at which it reappears when raised.
Along with tests for Total Coliform and E. Coli, SLCO takes readings three or four times per year in the main basin of the lake. The higher the number, the clearer the water.
Why it's important
Clear water allows light to penetrate deeper into the lake allowing for photosynthesis and oxygen production. Secchi depth is an indicator of lake health and is used in conjunction with nutrient concentrations from the laboratory analyses.
What the results show
The chart to the right indicates that Skeleton Lake's water is very clear with Secchi readings averaging over 9 meters (30 feet). The average for the other Muskoka lakes is 3 meters (10 feet) with a mean of 3.2 meters.