Gilman Stream Reservoir Report
Nearby: Hancock Pond Pennell Pond
Last Updated: December 19, 2025
Gilman Stream in Somerset, Maine is home to a historic hydroelectric dam completed in 1911.
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Summary
The dam, standing at a height of 8 feet and stretching 228 feet in length, serves multiple purposes including fire protection, stock maintenance, and hydroelectric power generation. With a storage capacity of 1600 acre-feet and a drainage area of 133 square miles, the dam has a maximum discharge of 835 cubic feet per second.
Managed by the Federal Energy Regulatory Commission, Gilman Stream Dam is classified as having a low hazard potential and a moderate risk assessment. The dam features an uncontrolled spillway and two slide gates for water release. Despite its age, the dam's condition assessment is not available, and its last inspection was conducted in September 2017 on a triennial basis. In case of emergencies, an Emergency Action Plan (EAP) may be in place, although details on its preparation and adherence to guidelines are not provided.
Overall, Gilman Stream Dam represents a significant piece of Maine's water infrastructure, providing essential services while also posing manageable risks. As a hydroelectric facility, it plays a role in regional energy production and water resource management. Continued monitoring and maintenance will be crucial to ensure the dam's safe operation and longevity in the face of changing climate conditions.
Year Completed |
1911 |
Dam Length |
228 |
Dam Height |
8 |
River Or Stream |
Gilman Stream |
Primary Dam Type |
Other |
Surface Area |
790 |
Drainage Area |
133 |
Nid Storage |
1600 |
Outlet Gates |
Slide (sluice gate) - 2 |
Hazard Potential |
Low |
Nid Height |
8 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Carrabassett River Near North Anson
|
304cfs |
Kennebec River At Bingham
|
1990cfs |
Austin Stream At Bingham
|
55cfs |
Sandy River Near Mercer
|
326cfs |
Dead River Near Dead River
|
791cfs |
Spencer Stream At Mouth
|
104cfs |
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.
Gilman Stream