Grassy Sprain Reservoir Dam

GRASSY SPRAIN BROOK· Westchester, New York· Built 1876· Earth· 40 ft tall
High Hazard Recreation Local Government

Key Takeaway

Grassy Sprain Reservoir Dam is classified as high hazard in New York. It was completed in 1876 and is 150 years old. Its primary use is recreation. 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 40 ft (taller than 88.1% in NY)
Dam Length600 ft
Dam TypeEarth
Max Storage3.6K acre-ft
Normal Storage3.0K acre-ft
Surface Area150 acres
Drainage Area2 sq mi
Max Discharge1,025 cfs
Year Completed1876 (150 years old)
NID IDNY00022

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

CITY OF YONKERS

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Grassy Sprain Reservoir Dam?

Grassy Sprain 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 Grassy Sprain Reservoir Dam?

Grassy Sprain Reservoir Dam is owned by CITY OF YONKERS (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Grassy Sprain Reservoir Dam built?

Grassy Sprain Reservoir Dam was completed in 1876, making it 150 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 Grassy Sprain Reservoir Dam?

Grassy Sprain Reservoir Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Grassy Sprain Reservoir Dam?

Grassy Sprain Reservoir Dam has a dam height of 40 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 Grassy Sprain Reservoir Dam last inspected?

Grassy Sprain 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.