Located in Grant County near Coulee City, it was built as part of the Bureau of Reclamation's Columbia Basin Project.

This allows the water pumped from the Columbia River to fill the upper Grand Coulee, creating a large equalizing reservoir known as Banks Lake.

They were built to create Banks Lake, 27 miles (43 km) long as an equalizing reservoir, with storage capacity of 715,000 acre-feet for irrigation.

While not a part of the Dry Falls Dam, the Main Canal Headworks was expanded to add a six pump/generating units.

Included in the contract was the dam across the Grand Coulee, the approach channel, the headworks and control structure, and the initial reach to the main canal.