US Bridges

Mn 4 over Watonwan River

Fair

Watonwan County, Minnesota · 7.5 MI S of ST James · Structure no. 5965

Built
1941
84 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
117 ft
3 main spans
Daily traffic
1,300
2018 count
Owner
State
State Highway Agency

About this bridge

Mn 4 over Watonwan River is a prestressed concrete stringer/multi-beam or girder carrying Mn 4 over Watonwan River in Watonwan County, Minnesota. It was built in 1941, so it is 84 years old, older than the Minnesota average of 38.5 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 1,300 vehicles a day, roughly 9% of them trucks, projected to reach 1,400 by 2038. The structure is 117 ft (35.8 m) long and 44 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesMn 4
CrossesWatonwan River
Location7.5 MI S of ST James
RouteState Highway 4
CountyWatonwan County
StateMinnesota
Coordinates43.88402, -94.68591
Functional classRural Minor Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating49.7 US tons
Inventory rating29.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length117 ft (35.8 m)
Longest span38 ft (11.7 m)
Deck width44 ft (13.4 m)
Roadway width41 ft (12.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,300 (2018)
Projected traffic1,400 by 2038
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemNo

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 Mn 4 over Watonwan River built?

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

What condition is Mn 4 over Watonwan River 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 September 2024.

How much traffic does Mn 4 over Watonwan River carry?

About 1,300 vehicles per day (2018 count), of which roughly 9% are trucks.

How long is Mn 4 over Watonwan River?

The structure is 117 ft (35.8 m) long with a longest span of 38 ft (11.7 m) and a deck 44 ft wide.

Who owns Mn 4 over Watonwan River?

It is owned by the State Highway Agency.