US Bridges

Umptanum Road over Wilson Creek

Fair

Kittitas County, Washington · 00.41 E I-90 · Structure no. 081209000000000

Built
1966
59 years old
Condition
Fair
inspected March 2024
Type
Tee Beam
Concrete
Length
37 ft
1 main span
Daily traffic
5,039
2020 count
Owner
City
City or Municipal Highway Agency

About this bridge

Umptanum Road over Wilson Creek is a concrete tee beam carrying Umptanum Road over Wilson Creek in Kittitas County, Washington. It was built in 1966, so it is 59 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 5,039 vehicles a day, roughly 15% of them trucks, projected to reach 8,315 by 2040. The structure is 37 ft (11.3 m) long and 30 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesUmptanum Road
CrossesWilson Creek
Location00.41 E I-90
RouteCounty Highway 96937
CountyKittitas County
StateWashington
Coordinates46.98082, -120.55156
Functional classUrban Collector

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating47 US tons
Inventory rating28 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckOther
Main spans1
Design loadHS 20 + Mod
Structure length37 ft (11.3 m)
Longest span36 ft (11 m)
Deck width30 ft (9.1 m)
Roadway width29 ft (8.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,039 (2020)
Projected traffic8,315 by 2040
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.7 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Umptanum Road over Wilson Creek built?

It was built in 1966, making it 59 years old in 2025.

What condition is Umptanum Road over Wilson Creek 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 March 2024.

How much traffic does Umptanum Road over Wilson Creek carry?

About 5,039 vehicles per day (2020 count), of which roughly 15% are trucks.

How long is Umptanum Road over Wilson Creek?

The structure is 37 ft (11.3 m) long with a longest span of 36 ft (11 m) and a deck 30 ft wide.

Who owns Umptanum Road over Wilson Creek?

It is owned by the City or Municipal Highway Agency.