Lower Twin Lakes Dam is an earth dam located in Passaic County, New Jersey, built in 1927. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 10 ft10 ft tall and 210 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Lower Twin Lakes Dam
The primary purpose of Lower Twin Lakes Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Pompton Lakes Borough Mua (private). It impounds the Post Brook near Wayne.
The dam stands 10 feet tall and stretches 210 feet across, creates a reservoir covering 40 acres, has a storage capacity of 128 acre-feet, and collects water from a drainage area of 8 square miles. Completed in 1927, the structure is well-established, with more than 75 years of service.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. 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 06/23/2023.
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Location
| State | New Jersey |
| County | Passaic |
| Nearest City | Wayne |
| River/Stream | Post Brook |
| Coordinates | 41.00847, -74.29737 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 10 ft |
| Dam Height | 10 ft |
| Dam Length | 210 ft |
| Year Completed | 1927 (99 years old) |
Storage & Hydraulics
| NID Storage | 128 acre-ft |
| Normal Storage | 128 acre-ft |
| Surface Area | 40 acres |
| Drainage Area | 8 sq mi |
Ownership & Safety
| Purpose | Recreation |
| Owner | Pompton Lakes Borough Mua |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/23/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00227 |
| Federal ID | NJ00227 |
| More Info | State Dam Safety Program |