New Mill Pond Dam is an earth dam located in Suffolk County, New York, built in 1825. It carries a Low hazard potential classification.
Dam profile
NID height · 15 ft15 ft tall and 465 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 New Mill Pond Dam
The primary purpose of New Mill Pond Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Suffolk County Department of Public Works (local government). It impounds the Northeast Branch near Smithtown.
The dam stands 15 feet tall and stretches 465 feet across, creates a reservoir covering 109 acres, has a maximum storage capacity of 545 acre-feet, and collects water from a drainage area of 23 square miles. Completed in 1825, the structure is one of the older dams in the region, with over a century and a half of service.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. The most recent inspection on record was 11/22/2024.
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Location
| State | New York |
| County | Suffolk |
| Nearest City | Smithtown |
| River/Stream | Northeast Branch |
| Coordinates | 40.84278, -73.22806 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 465 ft |
| Year Completed | 1825 (201 years old) |
Storage & Hydraulics
| NID Storage | 545 acre-ft |
| Max Storage | 545 acre-ft |
| Normal Storage | 308 acre-ft |
| Surface Area | 109 acres |
| Drainage Area | 23 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Suffolk County Department of Public Works |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 11/22/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NY01516 |
| Federal ID | NY01516 |
| More Info | State Dam Safety Program |