Relief dam
Relief
Relief Dam, located in Tuolumne, California, is a privately-owned structure primarily used for hydroelectric purposes. Completed in 1909, this rockfill dam stands at a height of 140 feet and has a storage capacity of 15,600 acre-feet. The dam's reservoir covers a surface area of 223 acres and is fed by Summit Creek, making it a vital water resource in the region.
Managed and regulated by various state and federal agencies, including the Federal Energy Regulatory Commission, Relief Dam poses a high hazard potential due to its age and design. Despite its moderate risk assessment, the dam has not undergone a recent condition assessment, raising concerns about its structural integrity. Emergency Action Plans have been prepared, but their compliance with guidelines is unclear, highlighting the need for regular inspections and maintenance to ensure the safety and reliability of this essential water infrastructure for Baker Station and surrounding areas.
For water resource and climate enthusiasts, Relief Dam represents a historic feat in hydroelectric engineering but also serves as a reminder of the ongoing challenges in managing aging infrastructure. With its high hazard potential and limited condition assessment data, there is a pressing need for continued monitoring and risk management measures to safeguard the community and environment from any potential dam failure. The collaboration between state and federal agencies is crucial in ensuring the long-term resilience of Relief Dam and its contribution to the local water supply and energy generation.
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 Relief -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| W Walker R Blw L Walker R Nr Coleville | 627 cfs | → |
| W Walker R Nr Coleville | 591 cfs | → |
| Buckeye C Nr Bridgeport | 103 cfs | → |
| Lk Eleanor Div To Cherry Lake Nr Hetch Hetchy Ca | 1 cfs | → |
| Eleanor C Nr Hetch Hetchy Ca | 34 cfs | → |
| Robinson C At Twin Lks Outlet Nr Bridgeport | 128 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Relief .
Boat launches
Campgrounds
Fishing spots
Paddle runs
- Relief Reservoir Outlet To Confluence With Clark Fork
- Headwater Deadman Creek To Confluence With Middle Fork Stanislaus River
- Headwaters Kennedy Creek To Confluence With Middle Fork Stanislaus
- Headwaters To Wilderness Boundary
- Wilderness Boundary To Confluence With Middle Fork Stanislaus
- Hoover Wilderness Boundary To Leavitt Meadows Campground
Track Relief 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 Relief
Where does the data for Relief 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 Relief .