Anson Reservoir Report
Nearby: Abenaki Madison Paper Corp Log
Last Updated: December 24, 2025
Anson, also known as Upper Dam, is a private structure located in Madison, Maine, along the Kennebec River.
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Summary
Built in 1923, this concrete gravity dam stands at 36 feet tall and spans 630 feet in length. The dam serves multiple purposes including hydroelectric power generation, fire protection, stock maintenance, and recreation.
Managed by the Federal Energy Regulatory Commission, Anson has a storage capacity of 5,860 acre-feet and a maximum discharge rate of 82,500 cubic feet per second. Despite being categorized as having a low hazard potential, the dam is considered to have a very high risk due to its age and condition assessment being unavailable. The emergency action plan for the dam was last revised in December 2020, highlighting the importance of ongoing monitoring and maintenance to ensure the safety and functionality of this crucial water resource infrastructure for the region.
With its controlled spillway and four other controlled outlet gates, Anson plays a significant role in regulating water flow and ensuring water resource sustainability in the area. As a key component of Maine's hydroelectric infrastructure, Anson represents a blend of historical significance and modern energy production, making it a noteworthy site for water resource and climate enthusiasts to explore and analyze.
Year Completed |
1923 |
Dam Length |
630 |
Dam Height |
36 |
River Or Stream |
Kennebec River |
Primary Dam Type |
Concrete |
Surface Area |
698 |
Drainage Area |
3148 |
Nid Storage |
5860 |
Outlet Gates |
Other Controlled - 4 |
Hazard Potential |
Low |
Nid Height |
36 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Carrabassett River Near North Anson
|
304cfs |
Sandy River Near Mercer
|
326cfs |
Kennebec River At Bingham
|
2760cfs |
Austin Stream At Bingham
|
55cfs |
Kennebec River At North Sidney
|
6240cfs |
Dead River Near Dead River
|
791cfs |
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.
Anson