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.
Location
| State | New Jersey |
| County | Morris |
| Nearest City | Morristown |
| River/Stream | Whippany River |
| Coordinates | 40.81305, -74.48133 |
Physical Characteristics
| Dam Type | Masonry |
| NID Height | 14 ft |
| Dam Height | 14 ft |
| Dam Length | 145 ft |
| Year Completed | 1939 (87 years old) |
Storage & Hydraulics
| NID Storage | 349 acre-ft |
| Max Storage | 349 acre-ft |
| Normal Storage | 77 acre-ft |
| Surface Area | 20 acres |
| Drainage Area | 25 sq mi |
| Max Discharge | 4,255 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Town of Morristown |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 12/11/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00359 |
| Federal ID | NJ00359 |
| More Info | State Dam Safety Program |