Cushman No 1

Cushman No 1 is an arch dam located in Mason County, Washington, built in 1926. It carries a High hazard potential classification and has a fair condition assessment.

About Cushman No 1

The primary purpose of Cushman No 1 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 City Of Tacoma (public utility). It impounds the North Fork Skokomish River near Skokomish Indian Res.

The dam stands 272 feet tall and stretches 1,111 feet across, creates a reservoir covering 4,010 acres, has a maximum storage capacity of 482,757 acre-feet, and collects water from a drainage area of 95 square miles. Completed in 1926, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 05/19/2022.

At 272 feet, this dam is taller than 99% of all dams in the United States.

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 Washington 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 HazardFair ConditionEmergency Action Plan: Yes

Location

StateWashington
CountyMason
Nearest CitySkokomish Indian Res
River/StreamNorth Fork Skokomish River
Coordinates47.42283, -123.22257

Physical Characteristics

Dam TypeArch
NID Height272 ft
Dam Height235 ft
Dam Length1,111 ft
Year Completed1926 (100 years old)

Storage & Hydraulics

NID Storage482,757 acre-ft
Max Storage482,757 acre-ft
Normal Storage453,350 acre-ft
Surface Area4,010 acres
Drainage Area95 sq mi
Spillway TypeNone

Ownership & Safety

PurposeHydroelectric
OwnerCity of Tacoma
Owner TypePublic Utility
Hazard ClassificationHigh
Condition AssessmentFair
Last Inspection05/19/2022
Emergency Action PlanYes

Identifiers

NID IDWA00145
Federal IDWA00145
More InfoState Dam Safety Program

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