Ragged Lake Reservoir Report

Last Updated: December 22, 2025

Ragged Lake in Maine is a captivating hydroelectric dam that was completed in 1937.


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Summary

Situated in Piscataquis County, this dam on Ragged Stream serves multiple purposes including flood risk reduction, recreation, and water supply. With a height of 30 feet and a length of 1193 feet, Ragged Lake has a storage capacity of 30,490 acre-feet and covers a surface area of 2,786 acres.

Managed by the Federal Energy Regulatory Commission, Ragged Lake dam features a controlled spillway with a width of 54 feet and three slide gates for outlet control. Despite its low hazard potential, the dam is classified as having a very high risk due to its critical role in the region's water resource management. The dam's condition assessment is currently not available, but regular inspections are conducted every three years to ensure its structural integrity and safety.

Water resource and climate enthusiasts will appreciate Ragged Lake's contribution to fish and wildlife habitat, navigation, and energy production. With its scenic location in Millinocket and its pivotal role in the region's water management, Ragged Lake stands as a testament to the intersection of human ingenuity and environmental stewardship in harnessing the power of water resources for societal benefits.

Year Completed

1937

Dam Length

1193

Dam Height

30

River Or Stream

Ragged Stream

Surface Area

2786

Drainage Area

40

Nid Storage

30490

Outlet Gates

Slide (sluice gate) - 3

Hazard Potential

Low

Foundations

Rock

Nid Height

30
       
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.