North Twin - Dike 4
North Twin - Dike 4 is an earth dam located in Penobscot County, Maine, built in 1934. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About North Twin - Dike 4
The primary purpose of North Twin - Dike 4 is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. It impounds the West Branch Penobscot River near Millinocket.
The dam stands 11 feet tall and stretches 197 feet across, creates a reservoir covering 17,790 acres, has a maximum storage capacity of 346,000 acre-feet, and collects water from a drainage area of 1,877 square miles. Completed in 1934, the structure is well-established, with more than 75 years 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 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 08/10/2022.
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Location
| State | Maine |
| County | Penobscot |
| Nearest City | Millinocket |
| River/Stream | West Branch Penobscot River |
| Coordinates | 45.64392, -68.77868 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 11 ft |
| Dam Height | 11 ft |
| Dam Length | 197 ft |
| Year Completed | 1934 (92 years old) |
Storage & Hydraulics
| NID Storage | 346,000 acre-ft |
| Max Storage | 346,000 acre-ft |
| Normal Storage | 346,000 acre-ft |
| Surface Area | 17,790 acres |
| Drainage Area | 1,877 sq mi |
| Spillway Type | None |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner Type | Not Listed |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/10/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | ME83048 |
| Federal ID | ME00203S004 |
| More Info | State Dam Safety Program |