coulee
A dry canyon eroded by Pleistocene floods that cut into the lava beds of the Columbia Plateau in the western United States, the walls of which may resemble the Mesas common to the U.S. desert southwest. Grand Coulee Dam, in Eastern Washington, once the largest dam in the world, is named after the "Grand Coulee" which stands nearby.
If you ever visit Grand Coulee Dam, stay overnight in Electric City and be sure to catch the colored lightshow on the spillways after dark.
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