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Flathead Dam
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Flathead Dam Share Share

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Manderson, Wyoming
Irrigation
Privately owned
Built in 1979

Flathead Dam is an earth dam built on the Gomer Gulch River and is located in Manderson, Wyoming. It was built in 1979 for the purpose of irrigation.

The dam is privately owned by Buffalo Creek Farms (Casey & Beth Johnstone). It is also known as Enl of Flathead 7808R.

Location
Flathead Dam
Manderson, Wyoming, U.S.
Dam type
Earth
Dam type
Irrigation
Purpose
Unknown
Foundation type
Unknown
Core type
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Ownership Share Share
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Buffalo Creek Farms (Casey & Beth Johnstone)
Owner
Private

Flathead Dam is privately owned by Buffalo Creek Farms (Casey & Beth Johnstone).

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Construction Share Share
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1979
Completed
John W. Donnell
Dam designer
Gomer Gulch River
River built on
Flathead Dam was built in 1979.
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Metrics Share Share
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Summary
Dam length 1,600 feet
Dam height 40 feet
Structural height 45 feet
Hydraulic height 36 feet
Max discharge 275 cubic feet per second
Normal storage 417 acre feet
Surface area 29 acres
Drainage area 1 square miles
1,600 feet
Dam length

Length of the dam is defined as the length along the top of the dam. This also includes the spillway, powerplant, navigation lock, fish pass, etc., where these form part of the length of the dam. If detached from the dam, these structures should not be included.

40 feet
Dam height

Height of the dam is defined as the vertical distance between the lowest point on the crest of the dam and the lowest point in the original streambed.

45 feet
Structural height

Structural height of the dam is defined as the vertical distance from the lowest point of the excavated foundation to the top of the dam. Top of dam refers to the parapet wall and not the crest.

36 feet
Hydraulic height

Hydraulic height of the dam is defined as the vertical difference between the maximum design water level and the lowest point in the original streambed.

275 cubic feet per second
Max discharge

Number of cubic feet per second the spillway is capable of discharging when the reservoir is at its maximum designed water surface elevation.

417 acre feet
Normal storage

Normal storage is defined as the total storage space in a reservoir below the normal retention level, including dead and inactive storage and excluding any flood control or surcharge storage. For normally dry flood control dams, the normal storage will be a zero value.

29 acres
Surface area

Surface area, in acres, of the impoundment at its normal retention level.

1 square miles
Drainage area

Drainage area of the dam, in square miles, which is defined as the area that drains to a particular point (in this case, the dam) on a river or stream.

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Safety Share Share
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Significant
Downstream potential hazard

Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be located in areas with population and significant infrastructure.

No emergency action plan
Emergency action plan

An emergency action plan is defined as a plan of action to be taken to reduce the potential for property damage and loss of life in an area affected by a dam failure or large flood.

11/29/2017
Most recent inspection date

Inspections are every 5 years.

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About Share Share
Also known as Enl of Flathead 7808R
Distance to nearest town (miles) 25
Latitude 44
Longitude -107
NID ID (National ID) WY01653
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