Mamaroneck Reservoir Dam Reservoir Report
Last Updated: December 6, 2025
The Mamaroneck Reservoir Dam, located in Mamaroneck, New York, is a concrete dam completed in 1928 with a primary purpose of flood risk reduction along the Mamaroneck River.
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Summary
Standing at a height of 19 feet and a length of 185 feet, the dam has a storage capacity of 241 acre-feet and a maximum discharge rate of 4240 cubic feet per second. The dam is state-regulated by the New York State Department of Environmental Conservation, with regular inspections and enforcement to ensure its safety and functionality.
Despite its age, the Mamaroneck Reservoir Dam is facing some challenges, with a poor condition assessment and a high hazard potential. The dam's condition was last assessed in December 2018, and it is in need of maintenance and potential rehabilitation to improve its overall safety. The dam has an emergency action plan in place, but there are concerns about its effectiveness in meeting current guidelines. With a moderate risk level assigned, there is a need for continued risk management measures to address any potential vulnerabilities and ensure the dam's resilience in the face of climate change and extreme weather events.
For water resource and climate enthusiasts, the Mamaroneck Reservoir Dam represents a crucial piece of infrastructure that plays a vital role in flood risk reduction in the region. As efforts are made to address its current condition and potential risks, the dam serves as a reminder of the ongoing challenges faced in managing water resources and adapting to changing environmental conditions. With continued oversight and maintenance, the Mamaroneck Reservoir Dam will remain a key asset in protecting communities and ecosystems from the impacts of flooding and ensuring the sustainable management of water resources in the area.
Year Completed |
1928 |
Dam Length |
185 |
Dam Height |
19 |
River Or Stream |
MAMARONECK RIVER |
Primary Dam Type |
Concrete |
Surface Area |
18 |
Drainage Area |
15.24 |
Nid Storage |
241 |
Hazard Potential |
High |
Nid Height |
19 |
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.
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