The surface area of Quamichan Lake is with a maximum depth of and a mean depth of . The surrounding watershed for this large, shallow lake is . The lake is habitat to
algae and
trout. There are also Pumpkinseed (invasive sunfish) and catfish in the lake. Many migratory birds winter in the lake as it rarely freezes over in the winter. 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. Between 2010 and 2014, about 65,500 trout were added to the lake by a hatchery. In 2014, a trout refuge including 1,500 linear feet of a bubble aeration system was constructed by a collaboration between the
Municipality of North Cowichan, the Rotary Club of Duncan, TimberWest Forest Corporation, Woodmere Strata Corporation, Aquatech Environmental Systems and the Quamichan Watershed Stewardship Society. The provision of compressed air addresses a lack of oxygen in late summer caused by demise of algae. == Residential area ==