Howard A. Hanson Dam

High HazardNot Available ConditionEmergency Action Plan: Yes

Location

StateWashington
CountyKing
Nearest CityAUBURN
River/StreamGREEN
Coordinates47.27821, -121.78655

Physical Characteristics

Dam TypeRockfill
NID Height235 ft
Dam Length500 ft
Year Completed1962 (64 years old)

Storage & Hydraulics

NID Storage136,700 acre-ft
Max Storage136,700 acre-ft
Normal Storage26,000 acre-ft
Surface Area20,000 acres
Drainage Area221 sq mi
Max Discharge129,000 cfs
Spillway TypeControlled

Ownership & Safety

PurposeFlood Risk Reduction
OwnerUSACE - Seattle District
Owner TypeFederal
Hazard ClassificationHigh
Condition AssessmentNot Available
Last Inspection11/19/2025
Emergency Action PlanYes

Identifiers

NID IDWA00298
Federal IDWA00298
More InfoState Dam Safety Program

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