Middle Piney Lake Dam

Middle Piney Lake Dam is an earth dam located in Sublette County, Wyoming, built in 1940. It carries a High hazard potential classification and has a poor condition assessment.

About Middle Piney Lake Dam

The primary purpose of Middle Piney Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Usda Fs (federal). It impounds the Middle Piney Creek near Big Piney, Wy.

The dam stands 24 feet tall and stretches 125 feet across, creates a reservoir covering 200 acres, has a maximum storage capacity of 4,389 acre-feet, and collects water from a drainage area of 6 square miles. Completed in 1940, the structure is well-established, with more than 75 years of service.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 10/11/2017. That was 8 years ago, which is on the longer end for a high-hazard structure.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Wyoming dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.

High HazardPoor ConditionEmergency Action Plan: Yes

Location

StateWyoming
CountySublette
Nearest CityBig Piney, Wy
River/StreamMiddle Piney Creek
Coordinates42.60335, -110.56653

Physical Characteristics

Dam TypeEarth
NID Height24 ft
Dam Height24 ft
Dam Length125 ft
Year Completed1940 (86 years old)

Storage & Hydraulics

NID Storage4,389 acre-ft
Max Storage4,389 acre-ft
Normal Storage4,389 acre-ft
Surface Area200 acres
Drainage Area6 sq mi
Max Discharge1 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeRecreation
OwnerUSDA FS
Owner TypeFederal
Hazard ClassificationHigh
Condition AssessmentPoor
Last Inspection10/11/2017
Emergency Action PlanYes

Identifiers

NID IDWY01276
Federal IDWY01276
More InfoState Dam Safety Program

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