Thorson Group West

Thorson Group West is an earth dam located in Houston County, Minnesota, built in 1963. It carries a Significant hazard potential classification and has a poor condition assessment.

About Thorson Group West

The primary purpose of Thorson Group West 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 Mndnr-forestry (state). It impounds the Root River S Fork-tr near Hokah.

The dam stands 31 feet tall and stretches 275 feet across, creates a reservoir covering 0 acres, has a maximum storage capacity of 20 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1963, the structure is well into its service life at over 50 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 04/26/2023.

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Significant HazardPoor ConditionEmergency Action Plan: Not Required

Location

StateMinnesota
CountyHouston
Nearest CityHokah
River/StreamRoot River S Fork-tr
Coordinates43.72490, -91.63170

Physical Characteristics

Dam TypeEarth
NID Height31 ft
Dam Height29 ft
Dam Length275 ft
Year Completed1963 (63 years old)

Storage & Hydraulics

NID Storage20 acre-ft
Max Storage20 acre-ft
Normal Storage0 acre-ft
Surface Area0 acres
Drainage Area0 sq mi
Max Discharge636 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeFlood Risk Reduction
OwnerMNDNR-Forestry
Owner TypeState
Hazard ClassificationSignificant
Condition AssessmentPoor
Last Inspection04/26/2023
Emergency Action PlanNot Required

Identifiers

NID IDMN00344
Federal IDMN00344
More InfoState Dam Safety Program

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