Upper South Dam is a gravity dam located in Alpena County, Michigan, built in 1930. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 20 ft20 ft tall and 350 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Upper South Dam
The primary purpose of Upper South Dam is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. It impounds the Thunder Bay near Lachine.
The dam stands 20 feet tall and stretches 350 feet across, creates a reservoir covering 7,000 acres, has a maximum storage capacity of 55,000 acre-feet, and collects water from a drainage area of 182 square miles. Completed in 1930, the structure is well-established, with more than 75 years 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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 09/17/2019.
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Location
| State | Michigan |
| County | Alpena |
| Nearest City | Lachine |
| River/Stream | Thunder Bay |
| Coordinates | 45.02400, -83.79100 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 350 ft |
| Year Completed | 1930 (96 years old) |
Storage & Hydraulics
| NID Storage | 55,000 acre-ft |
| Max Storage | 55,000 acre-ft |
| Normal Storage | 40,100 acre-ft |
| Surface Area | 7,000 acres |
| Drainage Area | 182 sq mi |
| Max Discharge | 4,850 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner Type | Not Listed |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/17/2019 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MI00202 |
| Federal ID | MI00202 |
| More Info | State Dam Safety Program |