Lake Alta dam
Lake Alta
Lake Alta, located in Placer County, California, is a captivating water resource nestled in the picturesque city of Folsom. Managed by the local government, this reservoir serves multiple purposes including hydroelectric power generation, irrigation, and water supply. The dam, completed in 1862, stands at a height of 22 feet and has a storage capacity of 270 acre-feet, making it a vital component of the region's water infrastructure.
With a surface area of 23 acres and a drainage area of 0.08 square miles, Lake Alta plays a crucial role in regulating the flow of the Truckee North Fork American River. The dam's hazard potential is classified as high, yet its current condition is assessed as fair. Regular inspections are conducted to ensure the dam's safety and integrity, with the most recent assessment dated back to September 2017. In the event of an emergency, the reservoir's Emergency Action Plan is prepared and regularly reviewed to meet safety guidelines.
Water and climate enthusiasts will find Lake Alta to be a fascinating example of sustainable water management in California. Its historical significance, combined with its essential role in providing water resources for the region, underscores the importance of responsible stewardship and maintenance of this vital infrastructure. As climate change continues to impact water resources, Lake Alta stands as a testament to the resilience and adaptability of water systems in the face of evolving environmental challenges.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
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 Lake Alta -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Pilot C Bl Mutton Canyon Nr Georgetown Ca | 2 cfs | → |
| Nf American R A North Fork Dam Ca | 773 cfs | → |
| N Yuba R Bl Goodyears Bar Ca | 663 cfs | → |
| Deer C Nr Smartville Ca | 59 cfs | → |
| Pilot C Ab Stumpy Meadows Res Ca | 3 cfs | → |
| Donner C A Donner Lk Nr Truckee Ca | 10 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lake Alta.
Boat launches
- Iowa Hill Road Placer County
- Lake Spaulding Road 10260, Nevada City
- Fuller Lake Boating Site
- Oxbow Raft Put-In Site
- Mosquito Ridge Rd, California
- Meadow Lake Road Nevada County
Campgrounds
Fishing spots
Paddle runs
- Chamberlain Falls (Iowa Hill To Yankee Jim)
- One-Half Mile West Of Confluence With Fall Creek To Confluence With Jefferson Creek
- Langs Crossing Bridge To One-Half Mile West Of Confluence With Fall Creek (Boundary Of Nf And Private Land)
- Yankee Jim Road To Ponderosa Way (Shirttail)
- Generation And Giant Gaps (Tadpole To Colfax-Iowa Hill Road)
- Tunnel Run (Ralston Powerhouse To Greenwood)
Track Lake Alta in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Lake Alta
Where does the data for Lake Alta come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the High 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 above 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 dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Lake Alta.