New Mills Reservoir Report
Nearby: American Tissue Cascade Pond
Last Updated: December 17, 2025
New Mills is a historic masonry dam located in Gardiner, Maine, along the Cobbosseecontee River.
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Summary
Completed in 1885, this dam serves multiple purposes, including hydroelectric power generation, fire protection, stock pond, fish and wildlife habitat, flood risk reduction, recreation, and water supply. With a height of 22 feet and a length of 200 feet, it has a storage capacity of 4650 acre-feet and covers a surface area of 856 acres.
Owned and regulated by the local government and the Maine Emergency Management Agency (MEMA), New Mills is classified as a high hazard potential dam with a fair condition assessment as of the last inspection in October 2018. The dam has a spillway width of 100 feet and a hydraulic height of 17 feet. While the dam meets the state permitting, inspection, and enforcement requirements, there are no specific risk management measures or emergency action plans in place as of the latest data update in April 2021.
The New Mills dam plays a crucial role in the water resource management and climate resilience efforts in Kennebec County, Maine. As a key infrastructure for both energy production and environmental conservation, it stands as a testament to the region's commitment to sustainable development and water security. With ongoing monitoring and maintenance, New Mills continues to serve as a vital resource for the local community and contribute to the overall well-being of the surrounding ecosystem.
Year Completed |
1885 |
Dam Length |
200 |
Dam Height |
22 |
River Or Stream |
Cobbosseecontee |
Primary Dam Type |
Masonry |
Surface Area |
856 |
Hydraulic Height |
17 |
Drainage Area |
217 |
Nid Storage |
4650 |
Structural Height |
22 |
Hazard Potential |
High |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Cobbosseecontee Stream At Gardiner
|
138cfs |
Sheepscot River At North Whitefield
|
85cfs |
Kennebec River At North Sidney
|
2090cfs |
Nezinscot River At Turner Center
|
43cfs |
Androscoggin River Near Auburn
|
1770cfs |
Sandy River Near Mercer
|
326cfs |
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.
New Mills
Litchfield