Winnewana Dam is an earth dam located in Washtenaw County, Michigan, built in 1956. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 12 ft12 ft tall and 270 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Winnewana Dam
The primary purpose of Winnewana Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Mdnr Parks & Recreation (state). It impounds the Tributary to Portage River near Sugarloaf Lake Resort Area.
The dam stands 12 feet tall and stretches 270 feet across, creates a reservoir covering 280 acres, has a maximum storage capacity of 1,560 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1956, the structure is well into its service life at over 50 years old.
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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 06/05/2017.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Michigan |
| County | Washtenaw |
| Nearest City | Sugarloaf Lake Resort Area |
| River/Stream | Tributary to Portage River |
| Coordinates | 42.34861, -84.11065 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 12 ft |
| Dam Height | 12 ft |
| Dam Length | 270 ft |
| Year Completed | 1956 (70 years old) |
Storage & Hydraulics
| NID Storage | 1,560 acre-ft |
| Max Storage | 1,560 acre-ft |
| Normal Storage | 1,000 acre-ft |
| Surface Area | 280 acres |
| Drainage Area | 1 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Mdnr Parks & Recreation |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 06/05/2017 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MI00327 |
| Federal ID | MI00327 |
| More Info | State Dam Safety Program |