Great Stone dam
Great Stone
Great Stone, also known as Great Falls Dam, is a historic hydroelectric structure located in Lewiston - Auburn, Maine. Built in 1865, this concrete, gravity, and masonry dam stands at a height of 27 feet and spans 955 feet across the Androscoggin River. With a storage capacity of 1600 acre-feet and a surface area of 200 acres, Great Stone serves multiple purposes including hydroelectric power generation and water supply for the region.
Managed by the Federal Energy Regulatory Commission, Great Stone features a spillway width of 814 feet and utilizes seven slide gates for water control. Despite being categorized as having low hazard potential, the dam is subject to regular inspections every three years to ensure its structural integrity and safety. With a moderate risk assessment rating, risk management measures for Great Stone are closely monitored to safeguard against any potential emergencies or hazards that may arise due to its age and location.
As a key landmark in water resource management and hydroelectric power generation in Maine, Great Stone continues to play a vital role in the region's infrastructure. With its historical significance, impressive engineering design, and ongoing operational oversight, Great Stone stands as a testament to the enduring importance of responsible dam management in ensuring water security and sustainable energy production for communities along the Androscoggin River.
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 Great Stone -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Androscoggin River Near Auburn | 7,760 cfs | → |
| Nezinscot River At Turner Center | 43 cfs | → |
| Little Androscoggin River Near South Paris | 125 cfs | → |
| Cobbosseecontee Stream At Gardiner | 726 cfs | → |
| Presumpscot River At Westbrook | -999,999 cfs | → |
| Sheepscot River At North Whitefield | 312 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Great Stone .
Track Great Stone 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 Great Stone
Where does the data for Great Stone 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 Low 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 Great Stone .