Four Mile Dam, located in Alpena, Michigan, was completed in 1902 and serves as a crucial hydroelectric structure on Thunder Bay.
Wind
Humidity
With a height of 27 feet and a length of 520 feet, this gravity dam with multi-arch core types and rock foundations provides a storage capacity of 900 acre-feet and a maximum discharge of 27,000 cubic feet per second. The dam also offers recreational opportunities, covering a surface area of 90 acres within a drainage area of 1,260 square miles.
Managed by the Federal Energy Regulatory Commission, Four Mile Dam is classified as a high hazard potential structure due to its age and condition assessment not being available. Despite its risk level being assessed as very high, the dam has controlled spillways with a width of 361 feet and a series of 7 needle and 17 slide gates for water flow control. While the dam does not have a state jurisdiction, permitting, or enforcement oversight, it remains a significant feature in water resource management and climate adaptation efforts in the region, attracting water resource and climate enthusiasts with its historical significance and engineering marvel.
Year Completed |
1902 |
Dam Length |
520 |
Dam Height |
27 |
River Or Stream |
Thunder Bay |
Surface Area |
90 |
Drainage Area |
1260 |
Nid Storage |
900 |
Outlet Gates |
Needle - 7, Slide (sluice gate) - 17 |
Hazard Potential |
High |
Foundations |
Rock |
Nid Height |
27 |