Decorah Upper Milldam

Decorah Upper Milldam is a gravity dam located in Winneshiek County, Iowa, built in 1911. It carries a Low hazard potential classification.

About Decorah Upper Milldam

The primary purpose of Decorah Upper Milldam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Iowa Department Of Natural Resources (state). It impounds the Upper Iowa River near Lansing.

The dam stands 8 feet tall and stretches 300 feet across, creates a reservoir covering 70 acres, has a maximum storage capacity of 358 acre-feet, and collects water from a drainage area of 568 square miles. Completed in 1911, 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 10/01/2003. That was over 22 years ago.

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Low HazardNot Rated ConditionEmergency Action Plan: Not Required

Location

StateIowa
CountyWinneshiek
Nearest CityLansing
River/StreamUpper Iowa River
Coordinates43.32210, -91.68650

Physical Characteristics

Dam TypeGravity
NID Height8 ft
Dam Height8 ft
Dam Length300 ft
Year Completed1911 (115 years old)

Storage & Hydraulics

NID Storage358 acre-ft
Max Storage358 acre-ft
Normal Storage283 acre-ft
Surface Area70 acres
Drainage Area568 sq mi
Spillway TypeUncontrolled

Ownership & Safety

PurposeRecreation
OwnerIowa Department of Natural Resources
Owner TypeState
Hazard ClassificationLow
Condition AssessmentNot Rated
Last Inspection10/01/2003
Emergency Action PlanNot Required

Identifiers

NID IDIA01289
Federal IDIA01289
More InfoState Dam Safety Program

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