Thermalito Diversion Dam
Thermalito Diversion
Thermalito Diversion, located in Oroville, California, is a state-regulated structure on the Feather River designed by the Department of Water Resources (DWR) in 1967. This concrete dam stands at a height of 143 feet and serves a primary purpose of water supply, with additional functions including hydroelectric power generation. The dam has a storage capacity of 13,328 acre-feet and a spillway width of 560 feet.
With a hazard potential rated as high and a risk assessment indicating a very high level of risk, the Thermalito Diversion is closely monitored and inspected by both state and federal agencies. The Federal Energy Regulatory Commission oversees the regulatory and inspection aspects of the dam, ensuring its safe operation. The dam's emergency action plan is up to date, meeting guidelines to address potential risks and emergencies effectively.
Water resource and climate enthusiasts will appreciate the strategic location and design of the Thermalito Diversion, which plays a crucial role in water supply and hydroelectric power generation in the region. The dam's impressive structural features, such as its multi-arch core and controlled spillway, demonstrate its resilience and capacity to manage the flow of the Feather River. As a key component of California's water infrastructure, the Thermalito Diversion continues to be a vital asset in managing the state's water resources effectively and sustainably.
Inside the reservoir
The real shoreline of this water body, with a depth model scaled so the basin holds exactly its recorded storage. Drag to orbit, scroll to zoom, and use the slider to drain and refill it. Click anywhere on the basin for the modelled depth there.
How this is built. The shoreline is the National Hydrography
Dataset polygon for this water body (“Thermalito Diversion Pool”),
matched to the dam by proximity and confirmed by comparing its area with the
National Inventory of Dams surface area (agreement 0.829×).
Depth is modelled, not surveyed: the basin is shaped by distance from
shore — deep in open water, shallow in the bays — and scaled so its
volume equals the recorded storage. No national bathymetric survey exists for
US reservoirs. Treat the shoreline, area and volume as measured, and the depth
distribution as an informed approximation.
Above normal pool, water is shown rising within the normal-pool
shoreline. Where it would actually spread depends on the surrounding
terrain, which is not modelled here — a reservoir in a steep canyon barely
widens, one on flat ground can spread a long way. This is a depth and volume
figure, not an inundation map. Official inundation mapping for a dam
comes from its Emergency Action Plan.
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 Thermalito Diversion -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Butte C Nr Chico Ca | 111 cfs | → |
| Yuba R Nr Marysville Ca | 865 cfs | → |
| Deer C Nr Smartville Ca | 2 cfs | → |
| N Yuba R Bl Goodyears Bar Ca | 129 cfs | → |
| Sacramento R A Colusa Ca | 6,100 cfs | → |
| Bear R Nr Wheatland Ca | 22 cfs | → |
About Thermalito Diversion
Where does the data for Thermalito Diversion 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.
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