Manalapan Lake Dam

Manalapan Brook· Middlesex, New Jersey· Earth· 15 ft tall

High Hazard Recreation Local Government

Key Takeaway

Manalapan Lake Dam is classified as high hazard in New Jersey. 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	15 ft (taller than 51.4% in NJ)
Dam Length	213 ft
Dam Type	Earth
Max Storage	297 acre-ft
Normal Storage	136 acre-ft

Surface Area	39 acres
Drainage Area	25 sq mi
Max Discharge	2,500 cfs
NID ID	NJ00293

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: August 25, 2021

State Regulated: Yes

Regulatory Agency: NJDEP

Ownership

County of Middlesex, Engineering Department

Local Government

Nearby Dams

Cranbury S. River Basin B1 Dam

Middlesex, NJ

Low Hazard 30 ft

Helmetta Dam

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Significant Hazard 7 ft

Regency Monroe Pond Dam

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High Hazard 14 ft

Devoe Lake Dam

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High Hazard 15 ft

Duhernal Dam

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Significant Hazard 13 ft

Brainerd Lake Dam

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Significant Hazard 13 ft

Davidsons Mill Pond Dam

Middlesex, NJ

Significant Hazard 10 ft

Englishtown Lake Dam

Monmouth, NJ

Significant Hazard 13 ft

Frequently Asked Questions

What is the hazard classification of Manalapan Lake Dam?

Manalapan Lake 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 Manalapan Lake Dam?

Manalapan Lake Dam is owned by County of Middlesex, Engineering Department (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

What is the primary purpose of Manalapan Lake Dam?

Manalapan Lake 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 Manalapan Lake Dam?

Manalapan Lake Dam has a dam height of 15 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 Manalapan Lake Dam last inspected?

Manalapan Lake Dam was last inspected on August 25, 2021. 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.