Union Valley Dam
| Company type | Reservoir |
|---|---|
| Industry | Water storage, Hydroelectric power |
| Founded | 1963 |
| Headquarters | El Dorado County , United States |
Area served | El Dorado County, California |
| Owner | City of Sacramento (water rights) |
| Parent | Sacramento Municipal Utility District |
Union Valley Reservoir is a reservoir situated in the eastern part of El Dorado County, California, approximately northeast of Placerville. Positioned within the boundaries of Eldorado National Forest in the Sierra Nevada, the reservoir rests at an elevation of .
The reservoir was formed in through the construction of the Union Valley Dam, an earth and rockfill structure on Silver Creek, which feeds into the American River. This reservoir is incorporated into the Upper American River Project, managed by the Sacramento Municipal Utility District, a public electric utility overseeing several dams across the area. Visitors to the lake can engage in recreational pursuits such as boating, fishing, and camping.
Union Valley Reservoir functions by capturing snowmelt runoff during spring and releasing water during summer to meet peak electricity demands downstream at hydroelectric facilities. The Union Valley Powerhouse, located at the dam’s base, has a generating capacity of 46.7 MW and operates primarily as a peaking power plant. The City of Sacramento, California holds the water rights associated with this reservoir.
The inflow sources for Union Valley Reservoir include Big Silver Creek, Jones Fork Silver Creek, Tells Creek, and Wench Creek. Outflows are managed through Robbs Peak and Jones Fork powerhouses. Specifically, water routed through Jones Fork Powerhouse originates from Ice House Reservoir, whereas Robbs Peak Powerhouse utilizes water from the headwaters of the Middle Fork American River via Loon Lake Reservoir along with smaller reservoirs situated on Gerle Creek and South Fork Rubicon River. Downstream of Union Valley Dam, Silver Creek’s flow is diverted through two additional powerhouses before it merges with the South Fork American River near Pollock Pines, California. Prior to the construction of the reservoir, Silver Creek’s flow was intermittent and supplemented by diversions from the Middle Fork American River.
See also
- List of dams and reservoirs in California
- List of lakes in California
- List of largest reservoirs of California
- List of the tallest dams in the United States