Hayes Marsh Dam is an earth dam located in Merrimack County, New Hampshire, built in 1951. It carries a Low hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 10 ft10 ft tall and 240 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 Hayes Marsh Dam
The primary purpose of Hayes Marsh Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Nh Fish and Game Department (state). It impounds the Catamount Brook near Allenstown.
The dam stands 10 feet tall and stretches 240 feet across, creates a reservoir covering 29 acres, has a maximum storage capacity of 279 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1951, the structure is well into its service life at over 50 years old.
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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 09/27/2018.
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Location
| State | New Hampshire |
| County | Merrimack |
| Nearest City | Allenstown |
| River/Stream | Catamount Brook |
| Coordinates | 43.13870, -71.37460 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 10 ft |
| Dam Height | 10 ft |
| Dam Length | 240 ft |
| Year Completed | 1951 (75 years old) |
Storage & Hydraulics
| NID Storage | 279 acre-ft |
| Max Storage | 279 acre-ft |
| Normal Storage | 93 acre-ft |
| Surface Area | 29 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 243 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Nh Fish and Game Department |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 09/27/2018 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NH00516 |
| Federal ID | NH00516 |
| More Info | State Dam Safety Program |