Proposed Third Power Plant at Grand Coulee Dam

Engineering studies by the Bureau of Reclamation indicate a third power plant at Grand Coulee Dam with installed capacity 3,600,000 kw is technically and economically feasible. This site, with existing large storage capacity, high head, and its location with respect to downstream reregulatory pondage and Canadian upstream storage to be developed under the Columbia River Treaty, is the most logical and desirable location for adding generating capacity needed in the Pacific Northwest. The plant is economically well-justified with a benefit-cost ratio of 3.24 to 1. The third power plant will be located below the dam on the right bank of the Columbia River in the area now occupied by the right-bank switchyard. Proposed construction includes a forebay dam and forebay, the third power plant and switchyard, a permanent visitors center, and riverbank protective works. Modification of the two existing power-plants and left-bank switchyard and relocation of the right-bank switchyard is planned to accommodate the new facilities. Bureau-developed digital computer programs will be extensively used in design of the plant, with the first unit scheduled to go on line less than 8 yr after availability of funds. Construction program would be more or less continuous through completion of all twelve 300,000-kw units.