Geddes Dam
Geddes Dam is an earth dam located in Washtenaw County, Michigan, built in 1920. It carries a High hazard potential classification and has a fair condition assessment.
About Geddes Dam
The primary purpose of Geddes Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by City Of Ann Arbor (local government). It impounds the Huron River near Ypsilanti.
The dam stands 28 feet tall and stretches 274 feet across, creates a reservoir covering 261 acres, has a maximum storage capacity of 3,100 acre-feet, and collects water from a drainage area of 765 square miles. Completed in 1920, the structure is over a century old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. 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 07/31/2019.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Michigan dam safety program can provide more specific information about emergency planning for this structure.
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 | Ypsilanti |
| River/Stream | Huron River |
| Coordinates | 42.27100, -83.67130 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 28 ft |
| Dam Height | 28 ft |
| Dam Length | 274 ft |
| Year Completed | 1920 (106 years old) |
Storage & Hydraulics
| NID Storage | 4,250 acre-ft |
| Max Storage | 3,100 acre-ft |
| Normal Storage | 4,250 acre-ft |
| Surface Area | 261 acres |
| Drainage Area | 765 sq mi |
| Max Discharge | 14,400 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Recreation |
| Owner | City of Ann Arbor |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 07/31/2019 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MI00561 |
| Federal ID | MI00561 |
| More Info | State Dam Safety Program |