GIBSON DAM PROJECT HISTORY 

Gibson Dam was constructed in 1926-1929 by the US Bureau of Reclamation (USBR) as part of the Sun River Project. The project purpose for Gibson Dam was irrigation; however, during the construction two penstock outlets were provided for future hydroelectric generation. Gibson Dam lies within the Lewis & Clark National Forest , administered by the USFS. 

Gibson Dam impounds Gibson Reservoir, a 5.5-mile long by 1-mile wide water body.  The drainage area above the reservoir is approximately 575 square miles.   

In 1989 the FERC issued a license for FERC Project No. 6863 to the Grisdale Hill Company for a hydroelectric development at Gibson Dam.  The license was for a Project with an installed capacity of 15 MW and a projected annual output of 46.1 GWH of energy. The Grisdale Hill License was subsequently surrendered to FERC.