US Bridges

IRR Road 305 over Watson Creek

Poor

Glenn County, California · Just East of Road 306 · Structure no. 11C0091

Built
1920
105 years old
Condition
Poor
inspected August 2023
Type
Tee Beam
Concrete Continuous
Length
81 ft
4 main spans
Daily traffic
120
2011 count
Owner
County
County Highway Agency

About this bridge

IRR Road 305 over Watson Creek is a concrete continuous tee beam carrying IRR Road 305 over Watson Creek in Glenn County, California. It was built in 1920, so it is 105 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.

It carries about 120 vehicles a day, roughly 10% of them trucks, projected to reach 166 by 2043. The structure is 81 ft (24.7 m) long and 18 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesIRR Road 305
CrossesWatson Creek
LocationJust East of Road 306
RouteCounty Highway 0
CountyGlenn County
StateCalifornia
Coordinates39.68023, -122.53036
Functional classRural Minor Collector

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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating30.8 US tons
Inventory rating18.5 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadUnknown
Structure length81 ft (24.7 m)
Longest span20 ft (6.1 m)
Deck width18 ft (5.6 m)
Roadway width17 ft (5.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic120 (2011)
Projected traffic166 by 2043
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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$533,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was IRR Road 305 over Watson Creek built?

It was built in 1920, making it 105 years old in 2025.

What condition is IRR Road 305 over Watson Creek 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 August 2023.

How much traffic does IRR Road 305 over Watson Creek carry?

About 120 vehicles per day (2011 count), of which roughly 10% are trucks.

How long is IRR Road 305 over Watson Creek?

The structure is 81 ft (24.7 m) long with a longest span of 20 ft (6.1 m) and a deck 18 ft wide.

Who owns IRR Road 305 over Watson Creek?

It is owned by the County Highway Agency.