Manchester Milldam

Manchester Milldam is a gravity dam located in Delaware County, Iowa, built in 1905. It carries a Low hazard potential classification.

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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Low HazardNot Rated ConditionEmergency Action Plan: Not Required

Location

StateIowa
CountyDelaware
Nearest CityManchester
River/StreamMaquoketa River
Coordinates42.48190, -91.45840

Physical Characteristics

Dam TypeGravity
NID Height11 ft
Dam Height11 ft
Dam Length201 ft
Year Completed1905 (121 years old)

Storage & Hydraulics

NID Storage395 acre-ft
Max Storage395 acre-ft
Normal Storage395 acre-ft
Surface Area70 acres
Drainage Area268 sq mi
Spillway TypeUncontrolled

Ownership & Safety

PurposeRecreation
OwnerAlliant Power Co
Owner TypePublic Utility
Hazard ClassificationLow
Condition AssessmentNot Rated
Last Inspection10/25/1989
Emergency Action PlanNot Required

Identifiers

NID IDIA01303
Federal IDIA01303
More InfoState Dam Safety Program

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