Mary Stock

Mary Stock is an earth dam located in Johnson County, Wyoming, built in 1970. It carries a Low hazard potential classification and has a poor condition assessment.

About Mary Stock

The primary purpose of Mary Stock is fire protection, stock, or small fish pond. The dam maintains a small impoundment used for fire suppression, livestock watering, or as a fish pond. The dam is owned by Aht Land, Llc (private). It impounds the Arpan Draw near Arvada.

The dam stands 38 feet tall and stretches 300 feet across, creates a reservoir covering 7 acres, and has a maximum storage capacity of 87 acre-feet. Completed in 1970, 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. 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 08/31/2022.

At 38 feet, this dam is taller than 85% of dams nationwide.

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Low HazardPoor ConditionEmergency Action Plan: Not Required

Location

StateWyoming
CountyJohnson
Nearest CityArvada
River/StreamArpan Draw
Coordinates44.49760, -106.31220

Physical Characteristics

Dam TypeEarth
NID Height38 ft
Dam Height38 ft
Dam Length300 ft
Year Completed1970 (56 years old)

Storage & Hydraulics

NID Storage87 acre-ft
Max Storage87 acre-ft
Normal Storage46 acre-ft
Surface Area7 acres
Spillway TypeUncontrolled

Ownership & Safety

PurposeFire Protection, Stock, Or Small Fish Pond
OwnerAHT LAND, LLC
Owner TypePrivate
Hazard ClassificationLow
Condition AssessmentPoor
Last Inspection08/31/2022
Emergency Action PlanNot Required

Identifiers

NID IDWY00443
Federal IDWY00443
More InfoState Dam Safety Program

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