Improving habitat for Trout: 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
the summer.
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.
- Diagram & Photos related to Aeration Equipment
- Ashley Report (PDF, 3 MB)
Sheldrake Lake Hypolimnetic Aeration Project: A Technical Overview of the Proposed Sheldrake Lake Hypolimnetic Aeration Project, prepared for WRWEO, Oct 6, 2001.