Portland is a gravity dam located in Ionia County, Michigan, built in 1919. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 15 ft15 ft tall and 680 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 Portland
The primary purpose of Portland is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. It impounds the Grand River near Lyons.
The dam stands 15 feet tall and stretches 680 feet across, creates a reservoir covering 30 acres, has a maximum storage capacity of 186 acre-feet, and collects water from a drainage area of 1,700 square miles. Completed in 1919, the structure is over a century 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 07/20/2022.
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Location
| State | Michigan |
| County | Ionia |
| Nearest City | Lyons |
| River/Stream | Grand River |
| Coordinates | 42.88910, -84.93080 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 15 ft |
| Dam Height | 9 ft |
| Dam Length | 680 ft |
| Year Completed | 1919 (107 years old) |
Storage & Hydraulics
| NID Storage | 186 acre-ft |
| Max Storage | 186 acre-ft |
| Normal Storage | 117 acre-ft |
| Surface Area | 30 acres |
| Drainage Area | 1,700 sq mi |
| Max Discharge | 2,400 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner Type | Not Listed |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/20/2022 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MI00099 |
| Federal ID | MI00099 |
| More Info | State Dam Safety Program |