US Bridges

San Andreas RD over Watsonville Slough

Poor

Santa Cruz County, California · 0.4 MI NW Beach RD · Structure no. 36C0027

Built
1941
84 years old
Condition
Poor
inspected May 2024
Type
Slab
Concrete Continuous
Length
90 ft
5 main spans
Daily traffic
6,000
2016 count
Owner
County
County Highway Agency

About this bridge

San Andreas RD over Watsonville Slough is a concrete continuous slab carrying San Andreas RD over Watsonville Slough in Santa Cruz County, California. It was built in 1941, so it is 84 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 6,000 vehicles a day, roughly 10% of them trucks, projected to reach 8,500 by 2041. The structure is 90 ft (27.4 m) long and 34 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesSan Andreas RD
CrossesWatsonville Slough
Location0.4 MI NW Beach RD
RouteCounty Highway 0
CountySanta Cruz County
StateCalifornia
Coordinates36.88775, -121.80486
Functional classRural Major 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
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 alignment6: Equal to present minimum criteria
Operating rating37.5 US tons
Inventory rating22.5 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadH 15
Structure length90 ft (27.4 m)
Longest span25 ft (7.6 m)
Deck width34 ft (10.4 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,000 (2016)
Projected traffic8,500 by 2041
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.7 mi (14 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$1.1 million (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was San Andreas RD over Watsonville Slough built?

It was built in 1941, making it 84 years old in 2025.

What condition is San Andreas RD over Watsonville 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 May 2024.

How much traffic does San Andreas RD over Watsonville Slough carry?

About 6,000 vehicles per day (2016 count), of which roughly 10% are trucks.

How long is San Andreas RD over Watsonville Slough?

The structure is 90 ft (27.4 m) long with a longest span of 25 ft (7.6 m) and a deck 34 ft wide.

Who owns San Andreas RD over Watsonville Slough?

It is owned by the County Highway Agency.