Mamaroneck Reservoir Dam

MAMARONECK RIVER· Westchester, New York· Built 1928· Concrete· 19 ft tall
High Hazard Flood Risk Reduction Local Government

Key Takeaway

Mamaroneck Reservoir Dam is classified as high hazard in New York. It was completed in 1928 and is 98 years old. Its primary use is flood risk reduction. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 19 ft (taller than 53.6% in NY)
Dam Length185 ft
Dam TypeConcrete
Max Storage241 acre-ft
Normal Storage18 acre-ft
Surface Area18 acres
Drainage Area15 sq mi
Max Discharge4,240 cfs
Year Completed1928 (98 years old)
NID IDNY00111

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: November 9, 2020
State Regulated: Yes
Regulatory Agency: NYS DEC

Ownership

VILLAGE OF MAMARONECK;Westchester Joint Waterworks

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Mamaroneck Reservoir Dam?

Mamaroneck Reservoir Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Mamaroneck Reservoir Dam?

Mamaroneck Reservoir Dam is owned by VILLAGE OF MAMARONECK;Westchester Joint Waterworks (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Mamaroneck Reservoir Dam built?

Mamaroneck Reservoir Dam was completed in 1928, making it 98 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Mamaroneck Reservoir Dam?

Mamaroneck Reservoir Dam serves the following purposes: Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Mamaroneck Reservoir Dam?

Mamaroneck Reservoir Dam has a dam height of 19 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Mamaroneck Reservoir Dam last inspected?

Mamaroneck Reservoir Dam was last inspected on November 9, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.