US Bridges

Skull Canyon Road over Birch Creek

FairPosted for load

Clark County, Idaho · 0.5 N. Blue Dome · Structure no. 000000000031623

Built
2001
24 years old
Condition
Fair
inspected July 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
22 ft
1 main span
Daily traffic
10
2023 count
Owner
County
County Highway Agency

About this bridge

Skull Canyon Road over Birch Creek is a wood or timber stringer/multi-beam or girder carrying Skull Canyon Road over Birch Creek in Clark County, Idaho. It was built in 2001, so it is 24 years old, younger than the Idaho average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 10 vehicles a day, roughly 10% of them trucks, projected to reach 15 by 2039. The structure is 22 ft (6.7 m) long and 18 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesSkull Canyon Road
CrossesBirch Creek
Location0.5 N. Blue Dome
RouteCounty Highway 0
CountyClark County
StateIdaho
Coordinates44.16019, -112.91225
Functional classRural Local

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; action required to protect exposed foundations
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 adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating30 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 length22 ft (6.7 m)
Longest span21 ft (6.4 m)
Deck width18 ft (5.5 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (2023)
Projected traffic15 by 2039
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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$291,000 (2018 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Skull Canyon Road over Birch Creek built?

It was built in 2001, making it 24 years old in 2025.

What condition is Skull Canyon Road over Birch 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 July 2024.

How much traffic does Skull Canyon Road over Birch Creek carry?

About 10 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Skull Canyon Road over Birch Creek?

The structure is 22 ft (6.7 m) long with a longest span of 21 ft (6.4 m) and a deck 18 ft wide.

Who owns Skull Canyon Road over Birch Creek?

It is owned by the County Highway Agency.