Cowichan Lake and River Stewardship Society



Water Quality and Fisheries Committee

Our priorities are...

  1. Continue monitoring water quality in the lake in the summer period to add on to the database already established.

  2. Report environmental concerns.

  3. Share information with BC Lake Stewardship Society, relevant government bodies and the public.

  4. Follow-up with the Lake Cowichan Marina to promote proper waste disposal.

2019 Report

Our sampling season began on May 5th and ran through until Sept. 8th during which we took 13 readings in both the north and south arms at the east end of Lake Cowichan.  Our readings reflected those of previous years with similar temperatures, excellent clarity & oxygenation levels.  The quality was best in the early spring and decreased over the summer, although the overall quality was still excellent when we stopped sampling in September.

We are indeed fortunate to live on and around this great natural resource!

Here are some observations from this years results:

Water Temperature Lowest 12.1 degrees on May 5th
Highest 21 degrees starting on July 28th, through to Sept. 8th


Water Oxygenation Level 

The higher the number, the better the quality of water.

Lowest 8.1 mg/litre of water, on Aug. 11th - still a very good number!


Highest 10.8g/litre of water, on May 5th


Water Clarity

Measured using a device called a secchi disk. You drop it into the water and measure the depth at which it is no longer visible.  The greater the depth, the clearer the water.

Average 10.8 meters (we did have some readings at 14.1 meters)

Many thanks to our volunteers who contributed 80+ hours of their summer time  to do the work and a special thanks to those volunteers who provided the boats which make this program possible!!

(Report submitted by Bee Greenway)



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Last updated: 09/30/19.