San Lorenzo Creek dam
San Lorenzo Creek
San Lorenzo Creek, also known as Don Castro Reservoir, is a vital water resource located in Castro Valley, California. Managed by the local government, this dam serves primarily for flood risk reduction and recreation purposes. Constructed in 1964, this earth dam stands at a height of 65 feet and has a storage capacity of 380 acre-feet, covering a surface area of 24 acres.
With a high hazard potential but assessed as satisfactory in condition, San Lorenzo Creek plays a crucial role in managing the region's water resources. The dam is regulated by the California Department of Water Resources and undergoes regular inspections to ensure its safety and reliability. Despite its age, the dam continues to provide flood protection and recreational opportunities for the local community.
San Lorenzo Creek's importance extends beyond flood risk reduction, serving as a significant water infrastructure in Alameda County. As climate change poses increasing challenges to water resources management, this dam remains a key asset in safeguarding against potential disasters and ensuring sustainable water use for the future. With its strategic location and vital role in the region, San Lorenzo Creek stands as a testament to the ongoing efforts to balance water resource management with environmental conservation and public safety.
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.
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near San Lorenzo Creek.
⚓ Boat launches
- Doolittle Drive 7250, Oakland
- Chelsea Drive 5094, Newark
- Lake Elizabeth Boat Ramp
- Mckay Avenue 1200, Alameda
- San Francisco Bay Trail, Oakland
- Whidbey Lane Redwood City
⛺ Campgrounds
- Anthony Chabot Family Campground
- Anthony Chabot Regional Park
- Bort Meadow Group Camp
- Corral Camp
- Camp Parks Military
- Alameda County Fairgrounds Rv
🎣 Fishing spots
More fishing →🛶 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.
- Olema Ranch Campground To Caltrans Corporation Yard At Point Reyes Station
- Gold Creek To Three Pools (Opal Creek Run)
🛡 More reservoirs
More reservoirs →Track San Lorenzo Creek 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 San Lorenzo Creek
Where does the data for San Lorenzo Creek 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 San Lorenzo Creek.