Millers Mills Dam Reservoir Report
Nearby: Burke Pond Dam Ilion Reservoir #2 Dam
Last Updated: December 6, 2025
Millers Mills Dam, also known as Unadilla Lake, is a privately owned structure located in Millers Mills, Herkimer County, New York.
°F
°F
mph
Wind
%
Humidity
Summary
Built in 1917, this earth dam stands at a height of 20 feet and stretches 200 feet in length, with a storage capacity of 200 acre-feet. The primary purpose of the dam is for recreation, with a surface area of 30 acres and a drainage area of 11.14 square miles along the Unadilla River.
The dam is regulated and permitted by the New York State Department of Environmental Conservation (NYS DEC), with state inspections and enforcement regularly conducted. Despite its low hazard potential, the dam's condition has not been rated recently, and risk assessment indicates a moderate level of risk. The spillway, which is uncontrolled, has a width of 40 feet, and the dam has not been modified in recent years, with the last inspection conducted in 1997.
For water resource and climate enthusiasts, Millers Mills Dam presents an intriguing case study of a historic structure that continues to serve a recreational purpose while being subject to state regulations and inspections. With its picturesque location and moderate risk assessment, the dam serves as a reminder of the importance of maintaining and monitoring critical infrastructure in the face of changing environmental conditions and potential hazards.
Year Completed |
1917 |
Dam Length |
200 |
Dam Height |
20 |
River Or Stream |
UNADILLA RIVER |
Primary Dam Type |
Earth |
Surface Area |
30 |
Drainage Area |
11.14 |
Nid Storage |
200 |
Hazard Potential |
Low |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Millers Mills Dam