Willow Hill Reservoir dam
Willow Hill Reservoir
Willow Hill Reservoir, located in Folsom, California, is a vital water supply facility owned by the local government. This reservoir is regulated by the Department of Water Resources (DWR) and falls under the jurisdiction of the state, ensuring proper permitting, inspection, and enforcement protocols are in place. With a primary purpose of water supply, Willow Hill Reservoir serves multiple uses including irrigation and tailings management.
This Earth-type dam stands at a height of 24 feet and has a hydraulic height of 20 feet, with a storage capacity of 125 acre-feet. The reservoir covers a surface area of 13 acres and has a drainage area of 0.06 square miles, offering a crucial water source for the region. Despite being classified as having a high hazard potential, Willow Hill Reservoir is currently assessed to be in fair condition as of September 2017, with regular inspections and emergency action plans in place to ensure the safety and functionality of the structure.
With its strategic location along the Tr American River, Willow Hill Reservoir plays a key role in water resource management in Sacramento County. As climate change continues to impact water availability and quality, reservoirs like Willow Hill are essential for ensuring a reliable water supply for agricultural, urban, and industrial needs in the region. Through diligent maintenance and risk management measures, Willow Hill Reservoir stands as a critical infrastructure supporting the community's water security and resilience in the face of changing environmental conditions.
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 Willow Hill Reservoir -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| American R A Fair Oaks Ca | 2,410 cfs | → |
| Deer C Nr Cameron Park Ca | 8 cfs | → |
| Dry C A Vernon St Bridge A Roseville Ca | 159 cfs | → |
| Cosumnes R A Michigan Bar Ca | 243 cfs | → |
| Arcade C Nr Del Paso Heights Ca | · | → |
| Laguna C Nr Elk Grove Ca | 1 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Willow Hill Reservoir.
Boat launches
- Willow Creek Boat Ramp
- Lake Natoma Northern Boat Ramp
- Jedediah Smith Memorial Trail, Gold River
- Green Valley Road 661, El Dorado Hills
- Pennsylvania Avenue 3885, Fair Oaks
- Park Road, Granite Bay
Fishing spots
Track Willow Hill Reservoir 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 Willow Hill Reservoir
Where does the data for Willow Hill Reservoir 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 Willow Hill Reservoir.