Coulee City, WA

Just west of Coulee City, highway US-2 crosses a dike holding back a sizable reservoir, Banks Lake, in a wide canyon, the Grand Coulee. (In Washington, “coulee” is a localism for a flat-bottomed canyon with steep sides).

Banks Lake resembles several storage reservoirs in the arid lands of the American West. It even has the usual recreational infrastructure such as marinas, boat-launch ramps, and bait shops. However, it is unusual, indeed unique, in a fundamental way: Grand Coulee is an abandoned Ice Age channel that carries no modern river.

Banks Lake is thus doubly artificial: not only does the dike hold back the water to make a lake, but the water itself was pumped up some 280 feet (85 meters) from the Columbia River using power from Grand Coulee Dam. (Grand Coulee Dam is not in the Grand Coulee. It’s on the Columbia River below the upper end of the coulee).

Why was all this effort expended? Banks Lake is the storage reservoir for the Columbia Basin (Irrigation) Project to the south. It can also be used as a power-storage reservoir. If water is run back through the pumps, the motors driving them to act as generators.