North Twin Reservoir Report
Last Updated: December 23, 2025
North Twin, also known as Elbow Lake Dam, is a hydroelectric facility located in Millinocket, Maine, along the West Branch Penobscot River.
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Summary
Constructed in 1934, this dam stands at a height of 35 feet and has a storage capacity of 346,000 acre-feet, serving multiple purposes such as flood risk reduction, recreation, and water supply. With a spillway width of 100 feet and a maximum discharge of 72,000 cubic feet per second, this dam plays a crucial role in managing water resources in the region.
Despite not being state-regulated, North Twin poses a high hazard potential, with a risk assessment rating of very high. Emergency action plans have been prepared, and the dam is inspected annually to ensure its structural integrity and safety. Managed by the Federal Energy Regulatory Commission, this dam serves as a key infrastructure for generating hydroelectric power while also supporting fish and wildlife habitats in the area. With its controlled spillway and outlet gates, North Twin is an essential component of the region's water resource management system.
Surrounded by scenic landscapes and offering recreational opportunities, North Twin Dam is a significant landmark in the Penobscot County, Maine. Its strategic location and design make it a vital asset for the community, balancing the need for energy production with environmental conservation and water management. As climate change continues to impact water resources, dams like North Twin play a crucial role in adapting to changing conditions and ensuring sustainable use of water for generations to come.
Year Completed |
1934 |
Dam Length |
1051 |
Dam Height |
35 |
River Or Stream |
West Branch Penobscot River |
Surface Area |
17790 |
Drainage Area |
1877 |
Nid Storage |
346000 |
Outlet Gates |
Slide (sluice gate) - 1, Tainter (radial) - 2 |
Hazard Potential |
High |
Nid Height |
35 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
East Branch Penobscot River At Grindstone
|
943cfs |
Mattawamkeag River Near Mattawamkeag
|
1130cfs |
Piscataquis River At Medford
|
880cfs |
Penobscot River At West Enfield
|
17000cfs |
Seboeis River Near Shin Pond
|
156cfs |
Piscataquis River Near Dover-Foxcroft
|
1160cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
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. Investigations and studies are necessary.
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.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams 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, environment 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.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Remote Site 5K
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Remote Site 5J
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Remote Site 4I
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Remote Site 3H
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Remote Sit 3G
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Remote Site 2F
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North Twin
trail Penobscot County
Ambajejus Falls
To The End Of North And South Twin Lakes