US Bridges

Orcas to Olga Road over Cascade Creek

Fair

San Juan County, Washington · Orcas Island · Structure no. 084419000000000

Built
1921
104 years old
Condition
Fair
inspected September 2024
Type
Arch - Deck
Concrete
Length
28 ft
1 main span
Daily traffic
1,607
2024 count
Owner
County
County Highway Agency

About this bridge

Orcas to Olga Road over Cascade Creek is a concrete arch - deck carrying Orcas to Olga Road over Cascade Creek in San Juan County, Washington. It was built in 1921, so it is 104 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 1,607 vehicles a day, roughly 5% of them trucks, projected to reach 1,700 by 2046. The structure is 28 ft (8.5 m) long and 18 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesOrcas to Olga Road
CrossesCascade Creek
LocationOrcas Island
RouteCounty Highway 4
CountySan Juan County
StateWashington
Coordinates48.64506, -122.83638
Functional classRural Minor 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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating16 US tons
Inventory rating10 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans1
Design loadUnknown
Structure length28 ft (8.5 m)
Longest span28 ft (8.5 m)
Deck width18 ft (5.5 m)
Roadway width16 ft (4.8 m)
Vertical clearance over deck14 ft (4.4 m)

Traffic and service

Average daily traffic1,607 (2024)
Projected traffic1,700 by 2046
Trucks5%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$939,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Orcas to Olga Road over Cascade Creek built?

It was built in 1921, making it 104 years old in 2025.

What condition is Orcas to Olga Road over Cascade 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 September 2024.

How much traffic does Orcas to Olga Road over Cascade Creek carry?

About 1,607 vehicles per day (2024 count), of which roughly 5% are trucks.

How long is Orcas to Olga Road over Cascade Creek?

The structure is 28 ft (8.5 m) long with a longest span of 28 ft (8.5 m) and a deck 18 ft wide.

Who owns Orcas to Olga Road over Cascade Creek?

It is owned by the County Highway Agency.