US Bridges

STC3830;W Id Blvd over Seven Mile Slough

Fair

Gem County, Idaho · 0.1 Sw. Letha · Structure no. 000000000019930

Built
1973
52 years old
Condition
Fair
inspected November 2023
Type
Tee Beam
Prestressed Concrete
Length
47 ft
2 main spans
Daily traffic
590
2023 count
Owner
County
County Highway Agency

About this bridge

STC3830;W Id Blvd over Seven Mile Slough is a prestressed concrete tee beam carrying STC3830;W Id Blvd over Seven Mile Slough in Gem County, Idaho. It was built in 1973, so it is 52 years old, older 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.

It carries about 590 vehicles a day, roughly 9% of them trucks, projected to reach 885 by 2042. The structure is 47 ft (14.3 m) long and 26 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesSTC3830;W Id Blvd
CrossesSeven Mile Slough
Location0.1 Sw. Letha
RouteCounty Highway 3830
CountyGem County
StateIdaho
Coordinates43.89392, -116.65222
Functional classRural Major 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
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 inspectionNovember 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 alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating36 US tons
Inventory rating21.1 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length47 ft (14.3 m)
Longest span22 ft (6.7 m)
Deck width26 ft (8 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic590 (2023)
Projected traffic885 by 2042
Trucks9%
Lanes on structure2
Traffic directionTwo-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 statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$590,000 (2019 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was STC3830;W Id Blvd over Seven Mile Slough built?

It was built in 1973, making it 52 years old in 2025.

What condition is STC3830;W Id Blvd over Seven Mile 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 November 2023.

How much traffic does STC3830;W Id Blvd over Seven Mile Slough carry?

About 590 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is STC3830;W Id Blvd over Seven Mile Slough?

The structure is 47 ft (14.3 m) long with a longest span of 22 ft (6.7 m) and a deck 26 ft wide.

Who owns STC3830;W Id Blvd over Seven Mile Slough?

It is owned by the County Highway Agency.