Mammoth Lake dam
Mammoth Lake
Mammoth Lake, located in Mount Pleasant Township, Pennsylvania, is a picturesque earth dam structure built in 1969 primarily for recreational purposes. With a height of 15 feet and a length of 1100 feet, this dam has a storage capacity of 342 acre-feet, making it a popular destination for outdoor enthusiasts in the Westmoreland County area. The lake covers a surface area of 27 acres and is fed by Wetley Run, providing a tranquil environment for fishing, boating, and other water-related activities.
Owned and regulated by the Pennsylvania Department of Environmental Protection, Mammoth Lake is regularly inspected to ensure its structural integrity and safety. Despite its high hazard potential, the dam's condition is deemed satisfactory, with a hazard potential rating of "High." The last inspection in August 2019 confirmed its soundness, reassuring visitors of its reliability for continued recreational use. As water resource and climate enthusiasts, you will appreciate the efforts taken to maintain this important water body for both enjoyment and environmental conservation in the region.
Mammoth Lake stands as a testament to the careful management of water resources in Pennsylvania, offering a serene retreat for locals and visitors alike. Its scenic beauty, combined with its essential role in providing recreational opportunities, highlights the importance of preserving and protecting our natural water sources. Whether you are interested in the engineering behind its construction or simply looking for a peaceful escape in nature, Mammoth Lake is sure to captivate water resource and climate enthusiasts with its blend of utility and charm.
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 Mammoth Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Loyalhanna Creek At Kingston | 115 cfs | → |
| Linn Run At Linn Run State Park Near Rector | 9 cfs | → |
| Youghiogheny River At Connellsville | 943 cfs | → |
| Conemaugh River At Tunnelton | 1,210 cfs | → |
| Loyalhanna Creek At Loyalhanna Dam | 221 cfs | → |
| Youghiogheny River At Sutersville | 1,120 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mammoth Lake.
Boat launches
- Acme Dam
- Lake Donegal #1 - Lake Under Drawdown
- Double Bridge Road Mount Pleasant Township
- Lake Donegal #2 - Lake Under Drawdown
- Jacobs Creek Park
- Legion-Keener Park
Campgrounds
- Keystone State Park
- Camp Ligonier
- Bush
- Kooser State Park
- Cedar Creek Trekker Campground
- Antiochian Village Camp
Fishing spots
- Bruceton Mills Public Fishing Area
- Frostburg Reservoir
- Sand Spring Run
- Deep Creek Lake
- Jennings Run
- Georges Creek
Track Mammoth Lake 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 Mammoth Lake
Where does the data for Mammoth Lake 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 Mammoth Lake.