US Bridges

SR 203 over Drainage Channel

Fair

King County, Washington · 7.7 N JCT SR 202 · Structure no. 0004656B0000000

Built
1954
71 years old, rebuilt 1998
Condition
Fair
inspected July 2023
Type
Slab
Concrete Continuous
Length
60 ft
3 main spans
Daily traffic
9,800
2023 count
Owner
State
State Highway Agency

About this bridge

SR 203 over Drainage Channel is a concrete continuous slab carrying SR 203 over Drainage Channel in King County, Washington. It was built in 1954 and reconstructed in 1998, so it is 71 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 9,800 vehicles a day, roughly 8% of them trucks, projected to reach 13,782 by 2039. The structure is 60 ft (18.3 m) long and 42 ft wide. If it were closed, the detour would be 13 mi (21 km).

Location

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CarriesSR 203
CrossesDrainage Channel
Location7.7 N JCT SR 202
RouteState Highway 203
CountyKing County
StateWashington
Coordinates47.67117, -121.90842
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53 US tons
Inventory rating32 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 15
Structure length60 ft (18.3 m)
Longest span22 ft (6.7 m)
Deck width42 ft (12.8 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,800 (2023)
Projected traffic13,782 by 2039
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed13 mi (21 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$1.2 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 203 over Drainage Channel built?

It was built in 1954, making it 71 years old in 2025. It was reconstructed in 1998.

What condition is SR 203 over Drainage Channel in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2023.

How much traffic does SR 203 over Drainage Channel carry?

About 9,800 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is SR 203 over Drainage Channel?

The structure is 60 ft (18.3 m) long with a longest span of 22 ft (6.7 m) and a deck 42 ft wide.

Who owns SR 203 over Drainage Channel?

It is owned by the State Highway Agency.