A coulee is a deep gulch or ravine carved out by water erosion, or a dry canyon forged by the Pleistocene floods that cut formations into lava beds of the Columbia Plateau thousands of years ago. That is, glaciers in that area retreated, leaving tremendous amounts of meltwater to flood the landscape and carve many landforms, including coulees. These broad, shallow depressions, which often have an underfit stream (a stream that seems too small for its valley) flowing through them like a ribbon, are a familiar part of the western landscape. The Grand Coulee, located in central Washington State, was an ancient dry riverbed six hundred feet above the Columbia River. Now it is the site of the massive Grand Coulee Dam—the largest concrete structure in the country— built under President Franklin D. Roosevelt to irrigate the arid areas of the Pacific Northwest. In 1941, when the dam was completed, the plan for irrigation was forgotten in lieu of the greater demands of war. Electricity from the Grand Coulee Dam was used to power aluminum mills and support production of uranium for the Manhattan Project; after the war, irrigation resumed. In the book Northwest Passage: The Great Columbia River, William Dietrich describes how “one can see the geographic logic of an idea that utterly changed the Pacific Northwest. The mesa is a kind of attention-getting monolith that almost demands to be climbed to its hurricane deck, but instead of a boat stair there is a steep, crumbling trail up a draw in the volcanic cliffs to the 800-foothigh plateau on top. . . . Paths wind away through bunch grass to its abrupt cliff, giving grand views of the Coulee, the reservoir, the blue bluffs of the distant Okanogan Highlands, and in spring a pencil line of green wheat along the Coulee’s rim.”

Elizabeth Cox