The Sheldrake Lake Hypolimnetic Aeration Project
The deeper parts of lakes (the hypolimnion) can become oxygen depleted
in summer through natural processes or as a result of human disturbance.
The deep areas are cooler waters where brook trout seek refuge in summer. As trout need oxygen, deep-water oxygen depletion eliminates important habitat for trout.
Surveys of lakes in the upper part of the Wooden’s River Watershed showed that several lakes become oxygen depleted at depth during
To maintain critical habitat for cool water fish such as trout, mechanical aeration systems are installed to aerate deep water that has become oxygen depleted. This is common practice in Europe and in some parts of North America (e.g., in British Columbia).
The aeration has to be a gentle process so as not to disturb the water stratification that maintains cooler waters at depth.
WRWEO volunteers fund-raised and in 2003/4 constructed the first lake aeration system in N.S. which is installed on Sheldrake Lake. In 2007, the Sheldrake Homeowners Association took
over responsibility of maintaining this system, with ongoing support from WRWEO.
In 2009, detailed monitoring of the lake was conducted by Bob Chembers to determine how well the aeration is working and to track long term trends in lake phosphorus. The aeration system was not working effectively, but there is some indication that phosphorus levels have declined. View Full Report by Bob Chambers (posted Aug. 16, 2010).
Possible improvements for the areation system have been discussed with the Sheldrake Homeowners Association.