US Bridges

River Road over Colusa Weir

Fair

Colusa County, California · 1.3 MI North of Colusa · Structure no. 15C0029

Built
1933
92 years old
Condition
Fair
inspected July 2023
Type
Tee Beam
Concrete
Length
1,737 ft
44 main spans
Daily traffic
1,224
2014 count
Owner
County
County Highway Agency

About this bridge

River Road over Colusa Weir is a concrete tee beam carrying River Road over Colusa Weir in Colusa County, California. It was built in 1933, so it is 92 years old, older than the California average of 54.8 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 1,224 vehicles a day, roughly 10% of them trucks, projected to reach 2,371 by 2041. The structure is 1,737 ft (529.4 m) long and 23 ft wide. If it were closed, the detour would be 31.7 mi (51 km).

Location

Open in Google Maps
CarriesRiver Road
CrossesColusa Weir
Location1.3 MI North of Colusa
RouteCounty Highway 0
CountyColusa County
StateCalifornia
Coordinates39.23212, -121.99587
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
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 inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating26.1 US tons
Inventory rating19.6 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans44
Design loadH 15
Structure length1,737 ft (529.4 m)
Longest span40 ft (12.2 m)
Deck width23 ft (6.9 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,224 (2014)
Projected traffic2,371 by 2041
Trucks10%
Lanes on structure2
Traffic directionTwo-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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was River Road over Colusa Weir built?

It was built in 1933, making it 92 years old in 2025.

What condition is River Road over Colusa Weir 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 2023.

How much traffic does River Road over Colusa Weir carry?

About 1,224 vehicles per day (2014 count), of which roughly 10% are trucks.

How long is River Road over Colusa Weir?

The structure is 1,737 ft (529.4 m) long with a longest span of 40 ft (12.2 m) and a deck 23 ft wide.

Who owns River Road over Colusa Weir?

It is owned by the County Highway Agency.