The Walla Walla District handed construction of the Lower Monumental project to its neighboring district in July 1962. At this point, the Walla Walla District had completed the design, awarded supply contracts, and begun construction on the first cofferdam. From here, the Seattle District would have full oversight of construction. The Walla Walla District would continue to provide real estate and design support, but the dam would be built by Seattle District engineers.