The lake has been raised by the Corra Linn Dam and has a dike system at the southern end, which, along with industry in the 1950s–70s, has changed the ecosystem in and around the water.

[1] Although oriented primarily in a north-south configuration, a western arm positioned roughly halfway up the length of the lake stretches 35 km to the City of Nelson.

The southerly drainage over the moraine eventually stopped and the Kootenay River began to follow its present course.

[8] These native populations used the lake and associated river systems as part of their seasonal migration and trading routes.

[10] The dam provides flood control and winter power generation by raising the normal water level by two meters.

The reason for the decline is not known; possibilities include reduced numbers of Mysis relicta (which had been introduced as a food source for the Kokanee in 1949)[12][13] into the west arm due to the increased control of water levels, the disruption of rearing habitat due to recurring drawdown of the lake, reduced productivity of benthos due to the reduction of the amount of nutrients into the lake (after the close of the fertilizer plant), overfishing in the 1960s to 1970s[4] or competition between the Mysis relicta and immature fish.

[13] In 1990 the lake's southern Kokanee stocks neared extinction, and an experimental fertilizing program was started, with some success.

[3] The remaining are scattered among a number of small towns and villages: In 1953 water quality in the lake was negatively affected when the Cominco phosphate fertilizer plant on the Kootenay River at Kimberley opened.

[12] Large quantities of phosphorus entered the Kootenay River; the cause of cyanobacterial blooms from the 1950s until the early 1970s.