Somenos Lake and Quamichan Lake are sister lakes in the Cowichan Watershed. Both lakes were formed when glaciers receded 11,000 years ago; both are shallow (seven metres deep) and bowl-shaped; and both can be expected to fill in and disappear in the next few thousand years.
At present, the two lakes share a common set of conditions:
- excessive nutrient loading from the farms and homes which surround the lakes
- insufficient "flushing" in summer due to reduced inflows and truncated outflows
- increased plant growth ("algae-blooms"), and
- eutrophication (reduced oxygen as the vegetation decomposes)
- intensified warming
The combination of oxygen reduction at the bottom and temperature increases at the surface forces indigenous fish into the middle layer, where there is still some oxygen and temperatures are not too warm. In most recent summers, even that habitable middle layer has disappeared, resulting in fish-kills.
Both lakes are now embraced by stewardship organizations.
Somenos Marsh Conservation Area
The Somenos Marsh Wildlife Society formed in 1986 to protect the undeveloped wetlands around Somenos Lake from the constant development pressures. In 2001, the Somenos Management Plan was developed, and the Somenos Management Committee was subsequently formed to provide oversight on the undeveloped lands surrounding the lake. In 2006, the area was declared the Somenos Marsh Conservation Area.
Quamichan Lake Watershed
In 2007 the Quamichan Watershed Stewardship Society ("Quamichan Stewards") was formed by residents and farmers living around Quamichan Lake who were concerned about its degrading condition. In consultation with a number of government agencies, they developed the Quamichan Watershed Management Plan, and are implementing conservation and education programs to improve the condition of the lake.
Somenos Creek is the outflow from Somenos Lake into the Cowichan River, while the primary streams into the lake are Richards, Averill, & Bings creeks. The outflow from Quamichan Lake is Quamichan Creek, which joins Somenos Creek before it reaches the Cowichan River. McIntyre Creek, and its tributary Elkington Creek, are the primary streams flowing into Quamichan Lake.
Somenos Management Plan
Madrone Consultants Ltd., August 2001
Quamichan Watershed Management Plan
Quamichan Watershed Working Group, October 2009