US Bridges

FM over Argo Slough

Fair

Lyon County, Iowa · 099431202 · Structure no. 000000000229621

Built
1977
48 years old
Condition
Fair
inspected July 2023
Type
Culvert
Concrete Continuous
Length
38 ft
3 main spans
Daily traffic
789
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Argo Slough is a concrete continuous culvert carrying FM over Argo Slough in Lyon County, Iowa. It was built in 1977, so it is 48 years old, older than the Iowa average of 45.5 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 789 vehicles a day, roughly 27% of them trucks, projected to reach 789 by 2043. The structure is 38 ft (11.6 m) long. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesFM
CrossesArgo Slough
Location099431202
RouteCounty Highway 0
CountyLyon County
StateIowa
Coordinates43.41396, -95.8805
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating43.1 US tons
Inventory rating25.8 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans3
Design loadH 20
Structure length38 ft (11.6 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic789 (2022)
Projected traffic789 by 2043
Trucks27%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$30,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was FM over Argo Slough built?

It was built in 1977, making it 48 years old in 2025.

What condition is FM over Argo 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 July 2023.

How much traffic does FM over Argo Slough carry?

About 789 vehicles per day (2022 count), of which roughly 27% are trucks.

How long is FM over Argo Slough?

The structure is 38 ft (11.6 m) long with a longest span of 12 ft (3.7 m).

Who owns FM over Argo Slough?

It is owned by the County Highway Agency.