Union Valley Reservoir
| Company type | Reservoir |
|---|---|
| Industry | Hydroelectric power, Recreation |
| 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 (SMUD) |
Union Valley Reservoir is a reservoir situated in the eastern part of El Dorado County, California, approximately northeast of Placerville. Positioned within the Eldorado National Forest in the Sierra Nevada mountain range, this body of water lies at an altitude of .
The reservoir was formed in through the construction of the Union Valley Dam, a high earth and rockfill structure on Silver Creek, which feeds into the American River. It is incorporated into the Upper American River Project, overseen by the Sacramento Municipal Utility District (SMUD). SMUD is responsible for operating this dam along with several others across the area. The reservoir offers recreational activities such as boating, fishing, and camping.
Union Valley Reservoir functions by capturing spring snowmelt and releasing water during summer months to meet peak electricity demands at downstream hydroelectric facilities. The Union Valley Powerhouse, located at the foot of the dam, has a generation capacity of 46.7 MW and operates as a peaking power plant to deliver power when demand surges. The City of Sacramento, California holds the water rights to this reservoir.
Its sources of inflow include Big Silver Creek, Jones Fork Silver Creek, Tells Creek, Wench Creek, as well as discharge from Robbs Peak and Jones Fork powerhouses. It is important to note that the Jones Fork Powerhouse utilizes water from Ice House Reservoir rather than Jones Fork Silver Creek. Meanwhile, Robbs Peak Powerhouse draws water originating from the headwaters of the Middle Fork American River via Loon Lake Reservoir, along with smaller reservoirs on Gerle Creek and South Fork Rubicon River. Downstream from Union Valley Dam, waters from Silver Creek are channeled through two additional powerhouses before merging with the South Fork American River near Pollock Pines, California. Prior to the establishment of the reservoir and associated diversions, Silver Creek was known to be an intermittent stream.
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