Manchester Milldam is a gravity dam located in Delaware County, Iowa, built in 1905. It carries a Low hazard potential classification.
Dam profile
NID height · 11 ft11 ft tall and 201 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 Manchester Milldam
The primary purpose of Manchester Milldam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Alliant Power Co (public utility). It impounds the Maquoketa River near Manchester.
The dam stands 11 feet tall and stretches 201 feet across, creates a reservoir covering 70 acres, has a maximum storage capacity of 395 acre-feet, and collects water from a drainage area of 268 square miles. Completed in 1905, 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. The most recent inspection on record was 10/25/1989. That was over 36 years ago.
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Location
| State | Iowa |
| County | Delaware |
| Nearest City | Manchester |
| River/Stream | Maquoketa River |
| Coordinates | 42.48190, -91.45840 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 11 ft |
| Dam Height | 11 ft |
| Dam Length | 201 ft |
| Year Completed | 1905 (121 years old) |
Storage & Hydraulics
| NID Storage | 395 acre-ft |
| Max Storage | 395 acre-ft |
| Normal Storage | 395 acre-ft |
| Surface Area | 70 acres |
| Drainage Area | 268 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Alliant Power Co |
| Owner Type | Public Utility |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 10/25/1989 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA01303 |
| Federal ID | IA01303 |
| More Info | State Dam Safety Program |