A bill to authorize the Secretary of the Interior to construct, operate and maintain hydro-electric powerplants at various existing water projects, and for other purposes.

(Measure passed Senate, amended)

Authorizes the Secretary of the Interior to construct, operate, and maintain the following hydroelectric powerplant projects and the necessary transmission facilities: (1) Friant powerplant, California; (2) Whiskeytown powerplant, California; (3) Canyon Ferry powerplant enlargement, Montana; (4) Yellowtail Afterbay powerplant, Montana; (5) Hoover Dam powerplant modifications, Arizona and Nevada; (6) Buffalo Bill Dam powerplant replacement, Wyoming; (7) Red Bluff powerplant, California; (8) Stony Gorge powerplant, California; (9) Monticello powerplant, California; (10) Boca powerplant, California and Nevada; (11) Prosser powerplant, California and Nevada; and (12) Blue Mesa powerplant, Colorado.

Stipulates that the hydroelectric power generated by such facilities shall be marketed by the Secretary of Energy through the existing Federal hydroelectric power marketing systems.

Directs the Secretary of the Interior and the Secretary of Energy, during the construction of powerplants authorized in this Act, to seek to minimize the loss of capacity, energy or both to power customers due to unit outages which result from such construction. Directs the Secretary of Energy to seek to maintain deliveries of capacity, energy or both at contract prices to customers affected by unit outages resulting from such construction.

Authorizes appropriations beginning in fiscal year 1981 to the Secretary of the Interior for the construction of an automated gate at Lake Helena, bank stabilization, replacement of fishery access, and other fish and wildlife and recreational facilities concurrent with the construction of the Canyon Ferry powerplant, Montana, enlargement.

Makes the authorization provided by this Act for the Canyon Ferry powerplant enlargement effective and final 20 months after the date of enactment of this Act. Declares that such authorization shall not become effective if the Secretary has reported to Congress that the project fails to meet contemporary tests of economic justification or creates significant adverse environmental effects.