Union Valley reservoir
Union Valley
Union Valley is a reservoir located in El Dorado County, California. The reservoir was created in 1963 with the construction of the Union Valley Dam, which is part of the American River watershed. The hydrology of Union Valley is primarily fed by the Rubicon River, and the reservoir provides water for hydroelectric power generation, irrigation, and municipal use. The area is also popular for recreational activities such as fishing, boating, camping, and hiking. The surrounding forests and hills are home to a diverse range of wildlife, including deer, elk, and black bears. The Union Valley Snowpack, which is a significant provider of water to the region, is particularly important for the agricultural community, with crops such as potatoes, grapes, and apples requiring water from the snowpack for irrigation.
Daily levels at Union Valley
Storage volume, pool elevation, and total release plotted from the operating agency's daily observations.
Storage
acre-ft · code 2
Pool Elevation
ft · code 1
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Union Valley -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Pilot C Ab Stumpy Meadows Res Ca | 3 cfs | → |
| Pilot C Bl Mutton Canyon Nr Georgetown Ca | 2 cfs | → |
| General C Nr Meeks Bay Ca | 2 cfs | → |
| Upper Truckee R At Hwy 50 Above Meyers Ca | 28 cfs | → |
| Blackwood C Nr Tahoe City Ca | 4 cfs | → |
| Upper Truckee R At S Upper Truckee Rd Nr Meyers Ca | 4 cfs | → |
About Union Valley
Where does the data for Union Valley come from?
Daily storage, pool elevation, and release rates are sourced from USGS, USBR, and USACE monitoring stations. Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
Storage observations are updated daily by the operating agency. The 15-day weather forecast refreshes throughout the day. Snoflo caches and renders the most recent observation -- check the "as of" timestamp on the storage card.
What does the Hazard hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card below for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this reservoir, set a threshold, and you'll get a push the moment conditions cross.