Speedwell Dam

Whippany River· Morris, New Jersey· Built 1939· Masonry· 14 ft tall
High Hazard Recreation Local Government

Key Takeaway

Speedwell Dam is classified as high hazard in New Jersey. It was completed in 1939 and is 87 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 14 ft (taller than 46.2% in NJ)
Dam Length145 ft
Dam TypeMasonry
Max Storage349 acre-ft
Normal Storage77 acre-ft
Surface Area20 acres
Drainage Area25 sq mi
Max Discharge4,255 cfs
Year Completed1939 (87 years old)
NID IDNJ00359

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: October 15, 2021
State Regulated: Yes
Regulatory Agency: NJDEP

Ownership

Town of Morristown

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Speedwell Dam?

Speedwell 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 Speedwell Dam?

Speedwell Dam is owned by Town of Morristown (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Speedwell Dam built?

Speedwell Dam was completed in 1939, making it 87 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 Speedwell Dam?

Speedwell 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 Speedwell Dam?

Speedwell Dam has a dam height of 14 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 Speedwell Dam last inspected?

Speedwell Dam was last inspected on October 15, 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.