The Balsam Meadow Pumped Storage Project is one of two pumped storage hydroelectric projects in the Southern Sierra. It uses a preexisting reservoir as a lower reservoir, a small upper reservoir, and a powerhouse between them. The upper reservoir, also known as the Balsam Forebay, is filled by water pumped up to it from the lower reservoir, known as Shaver Lake, and by water flowing down from another reservoir above it. The intake/outfall for the pumped storage project is at the top of a 7,500-foot-long tunnel bored through solid rock. At the other end, down below, is the Eastwood Powerhouse, in a cavity carved out of solid granite, 1,000 feet underground. The powerhouse has just one pump/turbine unit, with the capacity of generating 200 megawatts. Construction started in 1983 and ended in 1987, when the upper reservoir was filled. Balsam Meadow was the last part of the larger Big Creek Hydroelectric Project, which was developed between 1913 and 1987 to provide power for Los Angeles.
