US Bridges

Boulder Lake over Boulder Creek

Good

Trinity County, California · No Data Entered · Structure no. 051456000001090

Built
1987
38 years old
Condition
Good
inspected May 2023
Type
Slab
Prestressed Concrete
Length
44 ft
1 main span
Daily traffic
50
Owner
Federal
U.S. Forest Service

About this bridge

Boulder Lake over Boulder Creek is a prestressed concrete slab carrying Boulder Lake over Boulder Creek in Trinity County, California. It was built in 1987, so it is 38 years old, younger than the California average of 54.8 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 50 vehicles a day, projected to reach 75 by 2045. The structure is 44 ft (13.4 m) long and 16 ft wide.

Location

Open in Google Maps
CarriesBoulder Lake
CrossesBoulder Creek
LocationNo Data Entered
RouteFederal Lands Road 37N19
CountyTrinity County
StateCalifornia
Coordinates41.097, -122.789
Functional classRural Local

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 protection3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation*: *
Deck geometry7: Better than present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating—
Inventory rating—

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length44 ft (13.4 m)
Longest span43 ft (13.2 m)
Deck width16 ft (4.9 m)
Roadway width15 ft (4.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (—)
Projected traffic75 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Boulder Lake over Boulder Creek built?

It was built in 1987, making it 38 years old in 2025.

What condition is Boulder Lake over Boulder Creek 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 May 2023.

How much traffic does Boulder Lake over Boulder Creek carry?

About 50 vehicles per day (latest count).

How long is Boulder Lake over Boulder Creek?

The structure is 44 ft (13.4 m) long with a longest span of 43 ft (13.2 m) and a deck 16 ft wide.

Who owns Boulder Lake over Boulder Creek?

It is owned by the U.S. Forest Service.