Grand Coulee Dam the Columbia River formed the Grand Coulee, but it was revealed in the mid-late 20th century that massive floods from Lake Missoula carved most of the gorge. The earliest known proposal to irrigate the Grand Coulee with the Columbia River dates to 1892, when the "Coulee City News" and "The Spokesman Review" reported on a scheme by a man named Laughlin McLean to construct a dam across the Columbia River, high enough that water would back up into the Grand Coulee. A dam that size would have its reservoir encroach into Canada, which would violate treaties. Soon after the Bureau
Laser light show (Grand Coulee Dam) Laser light show (Grand Coulee Dam) "The laser light show" at Grand Coulee Dam, which began in 1989, is one of the largest light shows in the U.S.. The 37 minute show runs daily from Memorial Day through September 30. An addition of fireworks lights up the sky above the dam each Memorial Weekend Sunday and July 4. The Grand Coulee Dam premiered its first non-laser light show in 1957. Approximately 740 flood lamps near the base of the dam lit up the dam, but not enough water flooded down the spillway for the desired effect. Lasers for the show