Patterson dam
Patterson
Patterson Dam, located in El Dorado County, California, is a privately owned structure primarily used for water supply purposes, including irrigation and recreation. Completed in 1960, this earth dam stands at a height of 37 feet and has a storage capacity of 350 acre-feet. Situated on Deadman Creek, the dam serves as a vital resource for the local community while also providing opportunities for recreational activities.
Managed by the Natural Resources Conservation Service, Patterson Dam is regulated by the California Department of Water Resources for safety and enforcement. With a high hazard potential, the dam undergoes regular inspections to ensure its structural integrity. Despite its age, the condition assessment in 2017 deemed the dam to be satisfactory, providing a sense of security to nearby residents and stakeholders.
Although Patterson Dam has not undergone significant modifications in recent years, its emergency action plan is up to date as of March 2021. With a focus on safety and risk management, the dam continues to play a crucial role in water resource management in the region, highlighting the importance of infrastructure maintenance and preparedness in the face of climate variability and increasing water demands.
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 Patterson -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Deer C Nr Cameron Park Ca | 8 cfs | → |
| Cosumnes R A Michigan Bar Ca | 253 cfs | → |
| Pilot C Bl Mutton Canyon Nr Georgetown Ca | 2 cfs | → |
| Pilot C Ab Stumpy Meadows Res Ca | 3 cfs | → |
| Nf American R A North Fork Dam Ca | 542 cfs | → |
| American R A Fair Oaks Ca | 3,140 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Patterson.
Boat launches
- Rock Creek Road El Dorado County
- River Trail El Dorado County
- Forebay Road El Dorado County
- Sly Park Road, Pollock Pines
- Poho Ridge El Dorado County
- Green Valley Road 661, El Dorado Hills
Campgrounds
- Koa Placerville
- Finnon Lake
- Mother Lode River Center
- Sly Park
- Peninsula - Folsom Lake State Rec Area
- Pine Cone - Sly Park Recreation Area
Fishing spots
- Folsom Lake
- Natoma Lake
- Stumpy Meadows Lake
- Lake Clementine
- Pg&E Rock Creek Lake Fishing Access
- Lake Tabeaud
Paddle runs
- Chili Bar
- South Fork American River
- Coloma To Greenwood - (C To G)
- The Gorge
- Cosumnes Mine Road To Confluence With Steely Fork Cosumnes River
- Confluence With Dogtown Creek To West Nf Boundary
More reservoirs
Track Patterson 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 Patterson
Where does the data for Patterson 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 Patterson.