Twelve Mile Creek Watershed Site D-62-1

Twelve Mile Creek Watershed Site D-62-1 is an earth dam located in Union County, Iowa, built in 1985. It carries a Significant hazard potential classification and has a satisfactory condition assessment.

About Twelve Mile Creek Watershed Site D-62-1

The primary purpose of Twelve Mile Creek Watershed Site D-62-1 is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Union County Swcd (local government). It impounds the Tr- Twelve Mile Cr. near Afton.

The dam stands 35 feet tall and stretches 644 feet across, creates a reservoir covering 10 acres, has a maximum storage capacity of 315 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1985, the structure is 41 years old.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 06/10/2020.

At 35 feet, this dam is taller than 82% of dams nationwide.

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Significant HazardSatisfactory ConditionEmergency Action Plan: Not Required

Location

StateIowa
CountyUnion
Nearest CityAfton
River/StreamTr- Twelve Mile Cr.
Coordinates41.05180, -94.26700

Physical Characteristics

Dam TypeEarth
NID Height35 ft
Dam Height35 ft
Dam Length644 ft
Year Completed1985 (41 years old)

Storage & Hydraulics

NID Storage315 acre-ft
Max Storage315 acre-ft
Normal Storage67 acre-ft
Surface Area10 acres
Drainage Area0 sq mi
Spillway TypeUncontrolled

Ownership & Safety

PurposeFlood Risk Reduction
OwnerUnion County SWCD
Owner TypeLocal Government
Hazard ClassificationSignificant
Condition AssessmentSatisfactory
Last Inspection06/10/2020
Emergency Action PlanNot Required

Identifiers

NID IDIA02308
Federal IDIA02308
More InfoState Dam Safety Program

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