Decorah Lower Milldam

Decorah Lower Milldam is a gravity dam located in Winneshiek County, Iowa, built in 1973. It carries a Low hazard potential classification.

About Decorah Lower Milldam

The primary purpose of Decorah Lower 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 27 feet tall and stretches 500 feet across, creates a reservoir covering 80 acres, has a maximum storage capacity of 1,318 acre-feet, and collects water from a drainage area of 645 square miles. Completed in 1973, the structure is well into its service life at over 50 years 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
Coordinates43.33910, -91.64220

Physical Characteristics

Dam TypeGravity
NID Height27 ft
Dam Height27 ft
Dam Length500 ft
Year Completed1973 (53 years old)

Storage & Hydraulics

NID Storage1,318 acre-ft
Max Storage1,318 acre-ft
Normal Storage1,091 acre-ft
Surface Area80 acres
Drainage Area645 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 IDIA01288
Federal IDIA01288
More InfoState Dam Safety Program

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