Openaka Lake Dam is an earth dam located in Morris County, New Jersey, built in 1750. It carries a Significant hazard potential classification and has a poor condition assessment.
Dam profile
NID height · 20 ft20 ft tall and 250 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 Openaka Lake Dam
The primary purpose of Openaka Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Alexander Price (private). It impounds the Den Brook near Denville.
The dam stands 20 feet tall and stretches 250 feet across, creates a reservoir covering 9 acres, has a maximum storage capacity of 72 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1750, the structure is one of the older dams in the region, with over a century and a half 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 10/25/2023.
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Location
| State | New Jersey |
| County | Morris |
| Nearest City | Denville |
| River/Stream | Den Brook |
| Coordinates | 40.85658, -74.52690 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 250 ft |
| Year Completed | 1750 (276 years old) |
Storage & Hydraulics
| NID Storage | 72 acre-ft |
| Max Storage | 72 acre-ft |
| Normal Storage | 46 acre-ft |
| Surface Area | 9 acres |
| Drainage Area | 4 sq mi |
| Max Discharge | 600 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Alexander Price |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Poor |
| Last Inspection | 10/25/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00780 |
| Federal ID | NJ00780 |
| More Info | State Dam Safety Program |