Graham Lake Dam Reservoir Report

Last Updated: December 20, 2025

Graham Lake Dam, located in Ellsworth, Maine, is a captivating structure built in 1924 primarily for hydroelectric power generation and recreation purposes.


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Summary

The dam stands at a height of 43 feet and spans a length of 630 feet, with a storage capacity of 130,000 acre-feet and a maximum discharge of 24,000 cubic feet per second. The dam is classified as a concrete, earth, and gravity structure, with a controlled spillway measuring 80 feet wide.

Managed by the Federal Energy Regulatory Commission (FERC), Graham Lake Dam poses a high hazard potential due to its location on the Union River and its large storage capacity. Despite this risk, the condition assessment of the dam is not available, and it is subject to regular inspections with an inspection frequency of one year. The dam has three Tainter radial gates for outlet control, and its emergency action plan was last revised in December 2018.

Overall, Graham Lake Dam is a key infrastructure for water resource management and energy production in the region. With its historical significance dating back almost a century, the dam continues to play a vital role in the local community while also serving as a popular recreational destination. Climate and water resource enthusiasts will find the engineering and operational details of Graham Lake Dam fascinating, highlighting the importance of sustainable dam management in the face of evolving environmental challenges.

Year Completed

1924

Dam Length

630

Dam Height

43

River Or Stream

Union River

Surface Area

10300

Drainage Area

499

Nid Storage

130000

Outlet Gates

Tainter (radial) - 3

Hazard Potential

High

Nid Height

43
       
Seasonal Comparison

Weather Forecast

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. 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

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, 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.