US Bridges

State Route 1 NB over Watsonville Slough

Fair

Santa Cruz County, California · 05-SCR-001-R1.35-WAT · Structure no. 36 0090R

Built
1967
58 years old, rebuilt 1999
Condition
Fair
inspected November 2023
Type
Slab
Concrete Continuous
Length
107 ft
4 main spans
Daily traffic
19,500
2009 count
Owner
State
State Highway Agency

About this bridge

State Route 1 NB over Watsonville Slough is a concrete continuous slab carrying State Route 1 NB over Watsonville Slough in Santa Cruz County, California. It was built in 1967 and reconstructed in 1999, so it is 58 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 19,500 vehicles a day, roughly 5% of them trucks, projected to reach 32,094 by 2045. The structure is 107 ft (32.7 m) long and 41 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesState Route 1 NB
CrossesWatsonville Slough
Location05-SCR-001-R1.35-WAT
RouteState Highway 1
CountySanta Cruz County
StateCalifornia
Coordinates36.90257, -121.77911
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, 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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating45 US tons
Inventory rating34.6 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length107 ft (32.7 m)
Longest span28 ft (8.6 m)
Deck width41 ft (12.6 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,500 (2009)
Projected traffic32,094 by 2045
Trucks5%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was State Route 1 NB over Watsonville Slough built?

It was built in 1967, making it 58 years old in 2025. It was reconstructed in 1999.

What condition is State Route 1 NB over Watsonville Slough 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 November 2023.

How much traffic does State Route 1 NB over Watsonville Slough carry?

About 19,500 vehicles per day (2009 count), of which roughly 5% are trucks.

How long is State Route 1 NB over Watsonville Slough?

The structure is 107 ft (32.7 m) long with a longest span of 28 ft (8.6 m) and a deck 41 ft wide.

Who owns State Route 1 NB over Watsonville Slough?

It is owned by the State Highway Agency.