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  • Writer's pictureNepahwin Lake Watershed Stewardship Group

What the Secchi???

Tracking Water Clarity Trends in collaboration with the Lake Partner Program;

Measuring water clarity with a Secchi Disk

If you have noticed a decline in water clarity in recent years, you're not alone, and you're not wrong.

A small group of NLWSG volunteers have been taking water clarity - otherwise known as Secchi depth - readings at three standardized sites around Nepahwin to track trends and provide data that might help determine the cause.

The average Secchi depth (a measure of water clarity) in June from 1999-2018 was 5.7m. So far, all readings this June have been below 3m.

June 29, 2021 - Jess' toes aren't as visible as they once were. Taken at hip-depth, adjacent to the Stewart Beach Jumping Rock.

So what is going on??? Water clarity will be impacted by fluctuations in algae, detritus, dissolved organic carbon, and other suspended solids in the lake, which in turn may be influenced by shoreline development and climate change. Hopefully the data collected will help pinpoint the cause and point us to a solution.

Check out what our community scientists have recorded and learn more about the Lake Partner Program, Secchi depth readings and what could be causing the decline by visiting

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