US Bridges

390th ST over Small Stream

Good

Clayton County, Iowa · 091063101 · Structure no. 000000000362980

Built
1958
67 years old
Condition
Good
inspected October 2024
Type
Culvert
Concrete
Length
31 ft
2 main spans
Daily traffic
79
2022 count
Owner
County
County Highway Agency

About this bridge

390th ST over Small Stream is a concrete culvert carrying 390th ST over Small Stream in Clayton County, Iowa. It was built in 1958, so it is 67 years old, older than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 79 vehicles a day, projected to reach 79 by 2044. The structure is 31 ft (9.4 m) long. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries390th ST
CrossesSmall Stream
Location091063101
RouteCounty Highway 0
CountyClayton County
StateIowa
Coordinates42.65878, -91.60137
Functional classRural Minor Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionOctober 2024
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 alignment7: Better than present minimum criteria
Operating rating25.6 US tons
Inventory rating18.7 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadUnknown
Structure length31 ft (9.4 m)
Longest span14 ft (4.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic79 (2022)
Projected traffic79 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 390th ST over Small Stream built?

It was built in 1958, making it 67 years old in 2025.

What condition is 390th ST over Small Stream in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in October 2024.

How much traffic does 390th ST over Small Stream carry?

About 79 vehicles per day (2022 count).

How long is 390th ST over Small Stream?

The structure is 31 ft (9.4 m) long with a longest span of 14 ft (4.3 m).

Who owns 390th ST over Small Stream?

It is owned by the County Highway Agency.