Blackwater Dam - Dodge Estate Dike
Blackwater Dam - Dodge Estate Dike is a gravity dam located in Merrimack County, New Hampshire, built in 1941. It carries a High hazard potential classification.
About Blackwater Dam - Dodge Estate Dike
The primary purpose of Blackwater Dam - Dodge Estate Dike is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Usace - New England District (federal). It impounds the Blackwater River near Webster.
The dam stands 18 feet tall and stretches 400 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 93,400 acre-feet, and collects water from a drainage area of 128 square miles. Completed in 1941, the structure is well-established, with more than 75 years of service.
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. An emergency action plan is in place for this dam. The most recent inspection on record was 10/25/2022.
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 Hampshire 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 Hampshire |
| County | Merrimack |
| Nearest City | Webster |
| River/Stream | Blackwater River |
| Coordinates | 43.31472, -71.73357 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 18 ft |
| Dam Height | 18 ft |
| Dam Length | 400 ft |
| Year Completed | 1941 (85 years old) |
Storage & Hydraulics
| NID Storage | 93,400 acre-ft |
| Max Storage | 93,400 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 128 sq mi |
| Max Discharge | 42,800 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - New England District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 10/25/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH03847 |
| Federal ID | NH00001S001 |
| More Info | State Dam Safety Program |