How deep is Kootenay Lake?

Kootenay Lake’s maximum depth is 154 m, per the ILEC World Lake Database. Wikipedia’s own infobox states 150 m for the same figure — the two sources do not quite agree, so both are kept here rather than picking one.

Wikipedia also splits the lake’s average depth in two: 10 m in the West Arm against 45 m for the main lake. ILEC instead gives one lake-wide mean depth of 94 m, not split by arm.

Verified 2026-09-22 against Wikipedia and 2026-09-22 against ILEC.

Kootenay Lake is 104 km long and up to 5 km wide, both from Wikipedia’s infobox. Wikipedia's infobox states this as "Max. width."

ILEC’s record does not give a separate length or width figure; it lists a total surface area of 389 km² instead. Wikipedia's infobox does not state a surface area; this is ILEC's figure.

Verified 2026-09-22 against Wikipedia. Area verified 2026-09-22 against ILEC.

No — Kootenay Lake is a natural lake, not a reservoir created by a dam. Kootenay Lake is a natural lake, not a reservoir created by a dam. Its maximum level has been regulated since 1938 under an International Joint Commission Order of Approval, supervised by operation of the Corra Linn Dam on the outflowing Kootenay River; the Order sets no minimum level.

The gauge at Queens Bay reads 531.34 m right now, read 40 min ago. See water level for a full day of readings and the 24-hour change.

Verified on 2026-09-22 against the International Joint Commission’s Kootenay Lake page.

Kootenay Lake does not freeze over. ILEC's own field for this is "Freezing period: None."

Large, deep lakes are generally slow to freeze because they hold more heat through winter, and this one runs up to 154 m deep in places.

Verified on 2026-09-22 against the ILEC World Lake Database record.

Kootenay Lake’s water reads as clear and low in nutrients in ILEC’s record. ILEC's own water-clarity record for the lake, measured at Cape Horn in 1984, is a Secchi-disk transparency ranging 4.1 m to 14 m depending on season. The same record lists total phosphorus at 0.004 to 0.011 mg/l, a low, nutrient-poor reading, and notes an "unusual algal bloom" in the 1960s and early 1970s that is "not evident now," with phosphorus loading since returned to "historic levels prior to fertilizer plant input."

Verified on 2026-09-22 against the ILEC World Lake Database record.

This site’s data files hold no shipwreck records for Kootenay Lake, so nothing is claimed here either way.

The Kootenay Lake Historical Society keeps the region’s own maritime history, including the preserved S.S. Moyie sternwheeler at Kaslo; see klhs.bc.ca.