Vasona Percolating dam
Vasona Percolating
Vasona Percolating, also known as Vasona Reservoir, is a public utility water resource located in Los Gatos, California. This reservoir plays a crucial role in flood risk reduction, irrigation, and water supply in the region. Built in 1935, this earth dam stands at a height of 34 feet and has a hydraulic height of 22 feet, holding a storage capacity of 410 acre-feet. With a drainage area of 44.2 square miles, Vasona Percolating is situated on the Los Gatos Creek, serving as a vital water management infrastructure in Santa Clara County.
Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Vasona Percolating is regularly inspected to ensure its structural integrity and operational readiness. The dam has a high hazard potential due to its location and the surrounding urban development. Despite this, the condition assessment in 2017 deemed it satisfactory, with an inspection frequency of once per year. The emergency action plan (EAP) for the reservoir was last revised in September 2018, highlighting the proactive measures in place to address any potential risks or emergencies.
In addition to its flood risk reduction capabilities, Vasona Percolating provides essential water storage and management services for the local community. As climate change continues to impact water resources, the importance of well-maintained infrastructure like Vasona Percolating cannot be overstated. With a long history of service and a commitment to safety and regulation, this reservoir remains a critical asset in ensuring water security and resilience in Santa Clara County.
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 Vasona Percolating -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Saratoga C A Saratoga Ca | 5 cfs | → |
| Guadalupe R Abv Hwy 101 A San Jose Ca | 35 cfs | → |
| Coyote C Ab Hwy 237 A Milipitas Ca | 14 cfs | → |
| San Lorenzo R A Big Trees Ca | 48 cfs | → |
| Matadero C A Palo Alto Ca | 0 cfs | → |
| San Francisquito C A Stanford University Ca | 8 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Vasona Percolating.
Boat launches
- Stevens Creek Reservoir
- Mckean Road 22707-22725, San Jose
- Santa Clara County
- Palo Alto Boat Launch
- Oak Glen Avenue 17655, Morgan Hill
- San Francisco Bay Trail East Palo Alto
Campgrounds
- Sanborn - Skyline County Park
- Walk-In Camps
- Walden West Outdoor School
- Main Camp
- Frog Flat Camp
- Raymundo Campos
Fishing spots
Track Vasona Percolating 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 Vasona Percolating
Where does the data for Vasona Percolating 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 Vasona Percolating.