US Bridges

Government Dam RD over Blackfoot River

Fair

Caribou County, Idaho · 9.5 N. 8.8 E.Chesterfield · Structure no. 000000000023290

Built
1970
55 years old
Condition
Fair
inspected June 2023
Type
Tee Beam
Prestressed Concrete
Length
60 ft
1 main span
Daily traffic
50
2023 count
Owner
County
County Highway Agency

About this bridge

Government Dam RD over Blackfoot River is a prestressed concrete tee beam carrying Government Dam RD over Blackfoot River in Caribou County, Idaho. It was built in 1970, so it is 55 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 50 vehicles a day, roughly 25% of them trucks, projected to reach 75 by 2042. The structure is 60 ft (18.3 m) long and 20 ft wide. If it were closed, the detour would be 31.7 mi (51 km).

Location

Open in Google Maps
CarriesGovernment Dam RD
CrossesBlackfoot River
Location9.5 N. 8.8 E.Chesterfield
RouteCounty Highway 0
CountyCaribou County
StateIdaho
Coordinates43.00094, -111.72969
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.
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 protection7 GoodSome minor problems.
Last inspectionJune 2023
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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating38 US tons
Inventory rating23 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length60 ft (18.3 m)
Longest span59 ft (18 m)
Deck width20 ft (6.1 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2023)
Projected traffic75 by 2042
Trucks25%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed31.7 mi (51 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$630,000 (2017 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Government Dam RD over Blackfoot River built?

It was built in 1970, making it 55 years old in 2025.

What condition is Government Dam RD over Blackfoot River 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 June 2023.

How much traffic does Government Dam RD over Blackfoot River carry?

About 50 vehicles per day (2023 count), of which roughly 25% are trucks.

How long is Government Dam RD over Blackfoot River?

The structure is 60 ft (18.3 m) long with a longest span of 59 ft (18 m) and a deck 20 ft wide.

Who owns Government Dam RD over Blackfoot River?

It is owned by the County Highway Agency.