Murphys Afterbay dam
Murphys Afterbay
Murphys Afterbay, located in Calaveras, California, is a public utility facility primarily used for hydroelectric power generation and irrigation. The dam, completed in 1953, stands at a height of 42.5 feet and has a storage capacity of 31 acre-feet. The structure is regulated by the California Department of Water Resources and undergoes regular inspections to ensure its safety and compliance with state regulations.
Situated on Angels Creek, the Murphys Afterbay plays a crucial role in managing water resources in the region. The dam's controlled spillway and Tainter gates help regulate water flow and prevent flooding during periods of high discharge. With a hazard potential rated as high and a risk assessment indicating a very high risk level, the facility is closely monitored to mitigate potential threats and ensure the safety of surrounding communities and infrastructure.
Despite its age, the Murphys Afterbay continues to be a vital piece of California's water infrastructure, providing essential services for both energy production and agriculture. As climate change impacts water resources across the state, facilities like the Murphys Afterbay will play an increasingly important role in managing water supplies and mitigating the effects of a changing climate on the region's ecosystems and communities.
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 Murphys Afterbay -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Black C Nr Copperopolis Ca | 1 cfs | → |
| Big C Ab Whites Gulch Nr Groveland Ca | 1 cfs | → |
| Cherry C Bl Valley Dam Nr Hetch Hetchy Ca | 144 cfs | → |
| Cherry C Bl Dion R Holm Ph | 1,720 cfs | → |
| Cherry C Nr Early Intake Ca | 581 cfs | → |
| Tuolumne R Bl Early Intake Nr Mather Ca | 2,200 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Murphys Afterbay .
Boat launches
- Glory Hole Road 6503, Angels Camp
- Forest Route 1n10 Tuolumne County
- Merals Pool Put-In
- Forest Route 1n04, Groveland
Campgrounds
- Columbia Airport Campground
- Frogtown Rv Park
- Gloryhole Rec Area- Ironhorse - Usbr
- Glory Recreation Area
- Big Oak - Glory Hole Area - New Melones Lake
- Calaveras Big Trees State Park
Fishing spots
Paddle runs
- Confluence With North Fork And Middle Fork Stanislaus To Clark Flat
- Sandbar To Confluence With North Fork Stanislaus River
- Below Mckay's Reservoir To Confluence With Middle Fork Stanislaus River
- One Mile Downstream Of State Park Boundary In Sec 24, T5n, R15e To Mckay's Reservoir
- Calaveras Big Trees State Park Boundary In Sec 24, T5n, R15e To One Mile Downstream Of State Park Boundary In Sec 24, T5n, R15e
- One-Quarter Mile Downstream Of Forest Road 5n75 Bridge Crossing To Calaveras Big Trees State Park Boundary In Sec 24, T5n, R15e
Track Murphys Afterbay 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 Murphys Afterbay
Where does the data for Murphys Afterbay 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 Murphys Afterbay .