US Bridges

I-90 WB over Drainage Ditch

Good

Kittitas County, Washington · 20.2 E JCT SR 906 · Structure no. 002000190000000

Built
1972
53 years old
Condition
Good
inspected October 2024
Type
Culvert
Concrete Continuous
Length
21 ft
2 main spans
Daily traffic
16,832
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 WB over Drainage Ditch is a concrete continuous culvert carrying I-90 WB over Drainage Ditch in Kittitas County, Washington. It was built in 1972, so it is 53 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 16,832 vehicles a day, roughly 23% of them trucks, projected to reach 21,760 by 2039. The structure is 21 ft (6.4 m) long. If it were closed, the detour would be 1.2 mi (2 km).

CarriesI-90 WB
CrossesDrainage Ditch
Location20.2 E JCT SR 906
RouteInterstate 90
Coordinates47.21436, -121.11236
Functional classRural Principal Arterial - Interstate

Condition and inspection

Good

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

ComponentRatingMeaning
Channel and channel protection8 Very GoodNo problems noted.
Culvert7 GoodSome minor problems.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating60 US tons
Inventory rating36 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20 + Mod
Structure length21 ft (6.4 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,832 (2023)
Projected traffic21,760 by 2039
Trucks23%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$379,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-90 WB over Drainage Ditch built?

It was built in 1972, making it 53 years old in 2025.

What condition is I-90 WB over Drainage Ditch 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 October 2024.

How much traffic does I-90 WB over Drainage Ditch carry?

About 16,832 vehicles per day (2023 count), of which roughly 23% are trucks.

How long is I-90 WB over Drainage Ditch?

The structure is 21 ft (6.4 m) long with a longest span of 10 ft (3 m).

Who owns I-90 WB over Drainage Ditch?

It is owned by the State Highway Agency.