San Antonio Dam dam
San Antonio Dam
San Antonio Dam, also known as San Antonio Reservoir, is a Federal-owned structure located in Claremont, California. Built in 1956 by CESPL, this Earth-type dam stands at a height of 160 feet and spans 3850 feet across San Antonio Creek. With a storage capacity of 11,880 acre-feet, the dam primarily serves the purpose of flood risk reduction along with a maximum discharge capacity of 53,700 cubic feet per second.
Managed by the US Army Corps of Engineers, San Antonio Dam is considered to have a high hazard potential and undergoes regular inspections and risk assessments to ensure its structural integrity. The dam is equipped with an uncontrolled spillway and vertical lift outlet gates to manage water levels and mitigate flood risks effectively. The risk management measures implemented by USACE include continual monitoring, prioritizing activities to reduce risks, and engaging with emergency managers and the public to raise awareness and preparedness for potential dam-related emergencies.
In the face of severe weather events and changing water levels, San Antonio Dam remains a critical structure for flood control in the region. Through proactive risk management strategies and ongoing maintenance efforts, USACE is dedicated to ensuring the safety and functionality of the dam to protect surrounding communities and water resources.
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 San Antonio Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| San Antonio C A Riverside Dr Nr Chino Ca | 3 cfs | → |
| Chino C A Schaefer Avenue Nr Chino Ca | 0 cfs | → |
| Cucamonga C Nr Mira Loma Ca | 53 cfs | → |
| Lytle C Nr Fontana Ca | 56 cfs | → |
| Fontana Ph Forebay Spillway Nr Fontana Ca | · | → |
| Fontana Uwc Surface Div Nr Fontana Ca | 17 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near San Antonio Dam.
Boat launches
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Campgrounds
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Fishing spots
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River runs
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About San Antonio Dam
Where does the data for San Antonio Dam 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 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 dam, set a threshold, and you'll get a push the moment conditions cross.
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.