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.

High HazardFair ConditionEmergency Action Plan: Yes

Location

StateMichigan
CountyWashtenaw
Nearest CityYpsilanti
River/StreamHuron River
Coordinates42.27100, -83.67130

Physical Characteristics

Dam TypeEarth
NID Height28 ft
Dam Height28 ft
Dam Length274 ft
Year Completed1920 (106 years old)

Storage & Hydraulics

NID Storage4,250 acre-ft
Max Storage3,100 acre-ft
Normal Storage4,250 acre-ft
Surface Area261 acres
Drainage Area765 sq mi
Max Discharge14,400 cfs
Spillway TypeControlled

Ownership & Safety

PurposeRecreation
OwnerCity of Ann Arbor
Owner TypeLocal Government
Hazard ClassificationHigh
Condition AssessmentFair
Last Inspection07/31/2019
Emergency Action PlanYes

Identifiers

NID IDMI00561
Federal IDMI00561
More InfoState Dam Safety Program

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