US Bridges

Lawen Lane over Black Slough

Fair

Harney County, Oregon · 3.15 MI South of HWY 78 · Structure no. 25A74 C10800315

Built
1993
32 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
25 ft
1 main span
Daily traffic
123
2020 count
Owner
County
County Highway Agency

About this bridge

Lawen Lane over Black Slough is a wood or timber stringer/multi-beam or girder carrying Lawen Lane over Black Slough in Harney County, Oregon. It was built in 1993, so it is 32 years old, younger than the Oregon average of 49.9 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 123 vehicles a day, roughly 10% of them trucks, projected to reach 143 by 2025. The structure is 25 ft (7.6 m) long and 28 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesLawen Lane
CrossesBlack Slough
Location3.15 MI South of HWY 78
RouteCounty Highway C0108
CountyHarney County
StateOregon
Coordinates43.38854, -118.80916
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.1 US tons
Inventory rating21.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadHS 20
Structure length25 ft (7.6 m)
Longest span24 ft (7.3 m)
Deck width28 ft (8.5 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic123 (2020)
Projected traffic143 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Lawen Lane over Black Slough built?

It was built in 1993, making it 32 years old in 2025.

What condition is Lawen Lane over Black Slough 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 Lawen Lane over Black Slough carry?

About 123 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Lawen Lane over Black Slough?

The structure is 25 ft (7.6 m) long with a longest span of 24 ft (7.3 m) and a deck 28 ft wide.

Who owns Lawen Lane over Black Slough?

It is owned by the County Highway Agency.