US Bridges

SR 203 over Drainage Channel

Good

King County, Washington · 9.7 N JCT SR 202 · Structure no. 0003124A0000000

Built
1946
79 years old
Condition
Good
inspected September 2024
Type
Slab
Concrete Continuous
Length
43 ft
3 main spans
Daily traffic
9,478
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 1946, so it is 79 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 9,478 vehicles a day, roughly 9% of them trucks, projected to reach 13,330 by 2039. The structure is 43 ft (13 m) long and 40 ft wide. If it were closed, the detour would be 13 mi (21 km).

Location

Open in Google Maps
CarriesSR 203
CrossesDrainage Channel
Location9.7 N JCT SR 202
RouteState Highway 203
CountyKing County
StateWashington
Coordinates47.68833, -121.93833
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating38.3 US tons
Inventory rating29.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 15
Structure length43 ft (13 m)
Longest span10 ft (3.2 m)
Deck width40 ft (12.2 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,478 (2023)
Projected traffic13,330 by 2039
Trucks9%
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$686,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 203 over Drainage Channel built?

It was built in 1946, making it 79 years old in 2025.

What condition is SR 203 over Drainage Channel in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in September 2024.

How much traffic does SR 203 over Drainage Channel carry?

About 9,478 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is SR 203 over Drainage Channel?

The structure is 43 ft (13 m) long with a longest span of 10 ft (3.2 m) and a deck 40 ft wide.

Who owns SR 203 over Drainage Channel?

It is owned by the State Highway Agency.