Morning Don. The dam you are referring to is an earthen fill dam impounding Balsom Meadow Forebay. I dont remember the exact size but the lake is about 50 acres+/-. The dam is about 500 ft long and about 100 ft high. Strong emphasis on the word about. Last time I was there was in 1994. The lake gets its water from the tunnel connecting Huntington and Shaver Lakes.
A few miles above the marina at Shaver you will pass under a high voltage line(around 100Kv). Follow that powerline down to the right to a goodsized building. 1100 vertical feet straight down is Balsom Meadow Power House. The elivator ride is "E-Ticket"!! That PH is used as a "peaker plant". During high power usage times of the day the unit is used as a generator, drawing water from the forebay and dumping into Shaver. When the demand drops off the unit is shut down. Late in the evening the unit is restarted as a pump, running backwards, to pump water from Shaver back up to the forebay. When I was a Maint. Mech. I spent a lot of hours in that plant doing routine maint. There is one unit with about 200MW. The plant "went online" in 1983-84. Probably more info. than you wanted? Byron