Speedwell Dam

Speedwell Dam is a masonry dam located in Morris County, New Jersey, built in 1939. It carries a High hazard potential classification and has a satisfactory condition assessment.

About Speedwell Dam

The primary purpose of Speedwell Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Town Of Morristown (local government). It impounds the Whippany River near Morristown.

The dam stands 14 feet tall and stretches 145 feet across, creates a reservoir covering 20 acres, has a maximum storage capacity of 349 acre-feet, and collects water from a drainage area of 25 square miles. Completed in 1939, the structure is well-established, with more than 75 years of service.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 12/11/2023.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The New Jersey dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.

High HazardSatisfactory ConditionEmergency Action Plan: Yes

Location

StateNew Jersey
CountyMorris
Nearest CityMorristown
River/StreamWhippany River
Coordinates40.81305, -74.48133

Physical Characteristics

Dam TypeMasonry
NID Height14 ft
Dam Height14 ft
Dam Length145 ft
Year Completed1939 (87 years old)

Storage & Hydraulics

NID Storage349 acre-ft
Max Storage349 acre-ft
Normal Storage77 acre-ft
Surface Area20 acres
Drainage Area25 sq mi
Max Discharge4,255 cfs

Ownership & Safety

PurposeRecreation
OwnerTown of Morristown
Owner TypeLocal Government
Hazard ClassificationHigh
Condition AssessmentSatisfactory
Last Inspection12/11/2023
Emergency Action PlanYes

Identifiers

NID IDNJ00359
Federal IDNJ00359
More InfoState Dam Safety Program

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