US Bridges

Sycamore Slough RD over Sycamore Slough

PoorPosted for load

Colusa County, California · 0.6 MI N of Sachreiter RD · Structure no. 15C0113

Built
1915
110 years old
Condition
Poor
inspected October 2024
Type
Tee Beam
Concrete
Length
42 ft
1 main span
Daily traffic
70
2014 count
Owner
County
County Highway Agency

About this bridge

Sycamore Slough RD over Sycamore Slough is a concrete tee beam carrying Sycamore Slough RD over Sycamore Slough in Colusa County, California. It was built in 1915, so it is 110 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 70 vehicles a day, roughly 10% of them trucks, projected to reach 160 by 2042. The structure is 42 ft (12.8 m) long and 21 ft wide. If it were closed, the detour would be 11.2 mi (18 km).

CarriesSycamore Slough RD
CrossesSycamore Slough
Location0.6 MI N of Sachreiter RD
RouteCounty Highway 0
Coordinates39.09833, -121.99238
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating13.2 US tons
Inventory rating10 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length42 ft (12.8 m)
Longest span41 ft (12.5 m)
Deck width21 ft (6.3 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic70 (2014)
Projected traffic160 by 2042
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.2 mi (18 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$301,000 (2017 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Sycamore Slough RD over Sycamore Slough built?

It was built in 1915, making it 110 years old in 2025.

What condition is Sycamore Slough RD over Sycamore Slough in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in October 2024.

How much traffic does Sycamore Slough RD over Sycamore Slough carry?

About 70 vehicles per day (2014 count), of which roughly 10% are trucks.

How long is Sycamore Slough RD over Sycamore Slough?

The structure is 42 ft (12.8 m) long with a longest span of 41 ft (12.5 m) and a deck 21 ft wide.

Who owns Sycamore Slough RD over Sycamore Slough?

It is owned by the County Highway Agency.