North Twin - Dike 6 Reservoir Report
Nearby: Millinocket Lake North Twin - Dike 5
Last Updated: January 12, 2026
North Twin - Dike 6, also known as Ambajejus Lake Dike, is a crucial earth dam located in Millinocket, Maine, along the West Branch Penobscot River.
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Summary
Built in 1934 for hydroelectric purposes, this dam serves multiple functions including flood risk reduction, recreation, and water supply. With a height of 13 feet and a length of 680 feet, North Twin - Dike 6 has a storage capacity of 346,000 acre-feet and covers a surface area of 17,790 acres, making it a significant water resource in the region.
Managed by the Federal Energy Regulatory Commission, North Twin - Dike 6 faces a high hazard potential due to its critical role in the area's infrastructure. Despite its importance, the condition assessment of the dam is currently not available, highlighting the need for regular inspections and maintenance. In case of emergencies, the dam has two slide gates for water release, but there is no spillway in place. As a key structure in the region, ensuring the safety and stability of North Twin - Dike 6 is essential for the surrounding communities and the environment.
With a high risk assessment rating and limited information on risk management measures, North Twin - Dike 6 underscores the importance of proactive monitoring and emergency preparedness. As climate change continues to impact water resources and infrastructure, the resilience of dams like North Twin - Dike 6 becomes increasingly vital. Stakeholders, including the local community and regulatory agencies, must collaborate to address the potential risks and ensure the long-term sustainability of this essential water resource in Maine's Piscataquis County.
Year Completed |
1934 |
Dam Length |
680 |
Dam Height |
13 |
River Or Stream |
West Branch Penobscot River |
Surface Area |
17790 |
Drainage Area |
1877 |
Nid Storage |
346000 |
Outlet Gates |
Slide (sluice gate) - 2 |
Hazard Potential |
High |
Nid Height |
13 |
Seasonal Comparison
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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.
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North Twin - Dike 6
Golden Road Maine
Ambajejus Falls
To The End Of North And South Twin Lakes