Donald R. Wheeler (surprise Lake) Dam
Donald R. Wheeler (surprise Lake) Dam is an earth dam located in Morris County, New Jersey, built in 1909. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Donald R. Wheeler (surprise Lake) Dam
The primary purpose of Donald R. Wheeler (surprise Lake) Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Pequannock Properties, Llc (private). It impounds the East Branch Rockaway River near Montville.
The dam stands 22 feet tall and stretches 750 feet across, creates a reservoir covering 25 acres, has a maximum storage capacity of 190 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1909, the structure is over a century old.
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 12/19/2024.
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 | Montville |
| River/Stream | East Branch Rockaway River |
| Coordinates | 40.95315, -74.35688 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 750 ft |
| Year Completed | 1909 (117 years old) |
Storage & Hydraulics
| NID Storage | 190 acre-ft |
| Max Storage | 190 acre-ft |
| Normal Storage | 143 acre-ft |
| Surface Area | 25 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 155 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Pequannock Properties, LLC |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 12/19/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00256 |
| Federal ID | NJ00256 |
| More Info | State Dam Safety Program |