US Bridges

SR 20 over Methow River

Fair

Okanogan County, Washington · 22.1 E Chelan CO · Structure no. 0012559A0000000

Built
1984
41 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
409 ft
4 main spans
Daily traffic
1,478
2023 count
Owner
State
State Highway Agency

About this bridge

SR 20 over Methow River is a prestressed concrete stringer/multi-beam or girder carrying SR 20 over Methow River in Okanogan County, Washington. It was built in 1984, so it is 41 years old, younger 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 1,478 vehicles a day, roughly 9% of them trucks, projected to reach 1,838 by 2039. The structure is 409 ft (124.7 m) long and 43 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesSR 20
CrossesMethow River
Location22.1 E Chelan CO
RouteState Highway 20
CountyOkanogan County
StateWashington
Coordinates48.54431, -120.32419
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating31.1 US tons
Inventory rating19 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length409 ft (124.7 m)
Longest span124 ft (37.7 m)
Deck width43 ft (13.1 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,478 (2023)
Projected traffic1,838 by 2039
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 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$8.2 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 20 over Methow River built?

It was built in 1984, making it 41 years old in 2025.

What condition is SR 20 over Methow River 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 20 over Methow River carry?

About 1,478 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is SR 20 over Methow River?

The structure is 409 ft (124.7 m) long with a longest span of 124 ft (37.7 m) and a deck 43 ft wide.

Who owns SR 20 over Methow River?

It is owned by the State Highway Agency.