Lower Crystal Springs dam
Lower Crystal Springs
Lower Crystal Springs, also known as Crystal Springs Reservoir, is a gravity dam located in San Mateo, California, along the San Mateo Creek. Built in 1888, this dam serves as a crucial water supply source for the region, with a storage capacity of 57,910 acre-feet and a surface area of 1,323 acres. The dam stands at a height of 149 feet, with a hydraulic height of 138.8 feet, making it an essential infrastructure for water resource management in the area.
Managed by the local government, Lower Crystal Springs is regulated and inspected by the California Department of Water Resources for safety and compliance. Despite its high hazard potential, the dam's condition assessment in 2017 deemed it satisfactory, ensuring its continued functionality and security. With a history dating back over a century, Lower Crystal Springs remains a vital component of the region's water supply infrastructure, highlighting the intersection of historical significance and modern-day climate resilience efforts.
With its proximity to San Francisco and under the jurisdiction of San Mateo County, Lower Crystal Springs plays a key role in water management and climate adaptation strategies in the region. The dam's design and construction reflect a commitment to sustainable water supply practices, while its regular inspections and emergency preparedness measures ensure the safety of surrounding communities. Lower Crystal Springs stands as a testament to the intersection of water resource management, climate resilience, and historical preservation in California's evolving landscape.
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 Lower Crystal Springs -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| San Mateo C Bl Lo Crystal Sp Res Nr San Mateo Ca | 4 cfs | → |
| Pilarcitos C Bl Stone Dam Nr Hillsborough Ca | 4 cfs | → |
| Pilarcitos C A Half Moon Bay Ca | 10 cfs | → |
| San Francisquito C A Stanford University Ca | 6 cfs | → |
| San Gregorio C A San Gregorio Ca | 14 cfs | → |
| Matadero C A Palo Alto Ca | 0 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lower Crystal Springs.
Boat launches
- Sawyer Camp Trail San Mateo County
- J Hart Clinton Drive San Mateo
- San Andreas Trail San Bruno
- Whidbey Lane Redwood City
- San Francisco Bay Trail, South San Francisco
- San Francisco Bay Trail East Palo Alto
Campgrounds
- Sweetwood Group Camp
- Half Moon Bay State Beach
- Dispersed Camping
- Candlestick Rv Park
- Camp Jones Gulch Ymca
- San Mateo Memorial County Park
Fishing spots
Paddle runs
- Headwaters To Mouth
- Headwaters To Ends One Quarter Mile South Of Bear Valley Road Bridge Segment 1: Ends 1/4 Mile South Of Bear Valley Road Bridge Segment 2: Caltrans Corporation Yard At Point Reyes Staton.
- Gold Creek To Three Pools (Opal Creek Run)
- Olema Ranch Campground To Caltrans Corporation Yard At Point Reyes Station
More reservoirs
Track Lower Crystal Springs 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 Lower Crystal Springs
Where does the data for Lower Crystal Springs 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 Lower Crystal Springs.