As the chart shows, we’ve been tracking this data in Platte Lake for nearly 40 years. It helps us quantify and monitor what is happening in the lake.  Much of this historical data is available on our website.

This chart shows how the clarity of the water has improved over the last 40 years.  You can see almost three times as deep into the Lake as you could 40 years ago!

The Secchi disk, created in 1865 by Pietro Angelo Secchi SJ, is a circular disk used to measure water transparency in oceans and lakes. The disc is mounted on a pole or line, and lowered slowly down in the water. The depth at which the pattern on the disk is no longer visible is taken as a measure of the transparency of the water. This measure is known as the Secchi depth and is related to water turbidity.

(for more, see http://en.wikipedia.org/wiki/Secchi_disk)