Sempervirens dam
Sempervirens
Sempervirens, also known as Sempervirens Reservoir, is a state-owned earth dam located in Santa Cruz, California, within the stunning Big Basin Stake Park. Built in 1951, this dam stands at a height of 42 feet and serves the primary purpose of flood risk reduction. With a storage capacity of 78 acre-feet and a drainage area of 0.36 square miles, Sempervirens plays a crucial role in managing water resources in the region.
Managed by the California Department of Water Resources (DWR) and the Safety of Dams regulatory agency, Sempervirens is inspected regularly to ensure its structural integrity and safety. The dam is classified as having a significant hazard potential, although its condition has been assessed as satisfactory. Despite the dam's relatively small size in terms of storage and surface area, it plays a vital role in protecting the surrounding area from flooding and providing water supply.
As a site of both environmental and engineering significance, Sempervirens Creek and its associated reservoir continue to be a focal point for water resource and climate enthusiasts. With its strategic location within the Santa Cruz county, the dam remains a critical piece of infrastructure for flood risk reduction and water supply management in the region.
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 Sempervirens -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Pescadero C Nr Pescadero Ca | 16 cfs | → |
| Saratoga C A Saratoga Ca | 5 cfs | → |
| San Lorenzo R A Big Trees Ca | 45 cfs | → |
| San Gregorio C A San Gregorio Ca | 13 cfs | → |
| San Francisquito C A Stanford University Ca | 6 cfs | → |
| Matadero C A Palo Alto Ca | 0 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Sempervirens.
Boat launches
- Stevens Creek Reservoir
- Palo Alto Boat Launch
- Santa Clara County
- San Francisco Bay Trail East Palo Alto
- Mckean Road 22707-22725, San Jose
- Sawyer Camp Trail San Mateo County
Campgrounds
- Sky Meadow Group Camp
- Huckleberry Campground
- Wastahi Campground
- Big Basin Redwoods State Park
- Lane-Sunset Trail Camp
- Deer Meadow Group Campground
Fishing spots
Paddle runs
More reservoirs
Track Sempervirens 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 Sempervirens
Where does the data for Sempervirens 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 Significant 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 Sempervirens.