US Bridges

Marine DR over Marietta Slough

Good

Whatcom County, Washington · .3 E Nooksack R · Structure no. 080771000000000

Built
1978
47 years old
Condition
Good
inspected January 2023
Type
Tee Beam
Prestressed Concrete
Length
105 ft
1 main span
Daily traffic
4,009
2019 count
Owner
County
County Highway Agency

About this bridge

Marine DR over Marietta Slough is a prestressed concrete tee beam carrying Marine DR over Marietta Slough in Whatcom County, Washington. It was built in 1978, so it is 47 years old, younger 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 4,009 vehicles a day, roughly 1% of them trucks, projected to reach 4,500 by 2041. The structure is 105 ft (32 m) long and 32 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesMarine DR
CrossesMarietta Slough
Location.3 E Nooksack R
RouteCounty Highway 12790
CountyWhatcom County
StateWashington
Coordinates48.7908, -122.58319
Functional classRural Major Collector

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 inspectionJanuary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
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 rating36.4 US tons
Inventory rating22.2 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadH 20
Structure length105 ft (32 m)
Longest span105 ft (32 m)
Deck width32 ft (9.8 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,009 (2019)
Projected traffic4,500 by 2041
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$4.2 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Marine DR over Marietta Slough built?

It was built in 1978, making it 47 years old in 2025.

What condition is Marine DR over Marietta Slough 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 January 2023.

How much traffic does Marine DR over Marietta Slough carry?

About 4,009 vehicles per day (2019 count), of which roughly 1% are trucks.

How long is Marine DR over Marietta Slough?

The structure is 105 ft (32 m) long with a longest span of 105 ft (32 m) and a deck 32 ft wide.

Who owns Marine DR over Marietta Slough?

It is owned by the County Highway Agency.