The Blackwater Reservoir is a reservoir created behind a dam in the mountains above Kinlochleven in the western Scottish Highlands. At over 914m long, the dam is the longest in the Highlands.
The hydroelectric scheme was constructed in the early 1900s for the British Aluminium Company (later: British Alcan) and was designed by engineers Patrick Meik and Charles Meik. Chief assistant resident engineer was William Halcrow.