Ellis Dam Reservoir Report
Nearby: Sanborn Pond Foss Mill - Dike
Last Updated: December 19, 2025
Ellis Dam, located in Hinkley, Maine, along the Passagassawakeag River, was completed in 1850 and stands at a height of 15 feet with a hydraulic height of 13 feet.
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Summary
This rockfill dam serves primarily for flood risk reduction, providing a maximum storage capacity of 625 acre-feet, with a normal storage of 525 acre-feet. The dam has a surface area of 93 acres and a length of 235 feet, ensuring protection for the surrounding areas from potential inundation.
Managed by a private owner, Ellis Dam is regulated by the Maine Emergency Management Agency (MEMA) and is subject to state permitting, inspection, and enforcement. Despite its low hazard potential, the dam's condition assessment is currently not rated, with the last inspection conducted in 1997. The dam lacks an Emergency Action Plan (EAP) and updated emergency contacts, raising concerns about its readiness for potential incidents. While the dam has not been modified in recent years, there is a need for increased monitoring and risk assessment to ensure its continued safety and functionality in the face of changing climate patterns and water resource management challenges.
For water resource and climate enthusiasts, Ellis Dam represents a historical and functional piece of infrastructure in Maine with a vital role in flood risk reduction along the Passagassawakeag River. As climate change continues to impact water systems and increase the frequency of extreme weather events, the importance of maintaining and monitoring dams like Ellis Dam becomes increasingly crucial. With a focus on improving emergency preparedness, risk assessment, and condition monitoring, efforts to safeguard Ellis Dam will contribute to the resilience of the local community and surrounding ecosystems in the face of evolving environmental challenges.
Year Completed |
1850 |
Dam Length |
235 |
Dam Height |
15 |
River Or Stream |
Passagassawakeag |
Primary Dam Type |
Rockfill |
Surface Area |
93 |
Hydraulic Height |
13 |
Nid Storage |
625 |
Structural Height |
15 |
Hazard Potential |
Low |
Nid Height |
15 |
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.
Ellis Dam