Upper Afton

Upper Afton is a gravity dam located in Lincoln County, Wyoming, built in 1942. It carries a Low hazard potential classification and has a satisfactory condition assessment.

Hazard potentialLowFailure would cause limited damage
ConditionSatisfactoryBest of 4 ratings
Emergency action planNot reported
Last inspection07/24/2019
Height25 ft
Built194284 years ago

Dam profile

NID height · 25 ft
25 FT TWO-STORY HOUSEMEDIAN U.S. DAM · 24 FT

25 ft tall and 100 ft long, taller than 50% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.

About Upper Afton

The primary purpose of Upper Afton is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Swift Creek Power Company (private). It impounds the Swift Creek, Salt River near Afton, Wy.

The dam stands 25 feet tall and stretches 100 feet across, creates a reservoir covering 2 acres, has a maximum storage capacity of 22 acre-feet, and collects water from a drainage area of 24 square miles. Completed in 1942, the structure is well-established, with more than 75 years of service.

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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 07/24/2019.

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Location

StateWyoming
CountyLincoln
Nearest CityAfton, Wy
River/StreamSwift Creek, Salt River
Coordinates42.74170, -110.88410

Physical Characteristics

Dam TypeGravity
NID Height25 ft
Dam Height25 ft
Dam Length100 ft
Year Completed1942 (84 years old)

Storage & Hydraulics

NID Storage22 acre-ft
Max Storage22 acre-ft
Normal Storage22 acre-ft
Surface Area2 acres
Drainage Area24 sq mi
Max Discharge918 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeHydroelectric
OwnerSwift Creek Power Company
Owner TypePrivate
Hazard ClassificationLow
Condition AssessmentSatisfactory
Last Inspection07/24/2019
Emergency Action PlanNot Required

Identifiers

NID IDWY02932
Federal IDWY02932
More InfoState Dam Safety Program