US Bridges

US 18 over Drainage Ditch

Fair

Sioux County, Iowa · 2.3 Mi. E of Jct. SR K52 · Structure no. 000000000048311

Built
1976
49 years old
Condition
Fair
inspected March 2023
Type
Culvert
Concrete Continuous
Length
32 ft
3 main spans
Daily traffic
5,200
2022 count
Owner
State
State Highway Agency

About this bridge

US 18 over Drainage Ditch is a concrete continuous culvert carrying US 18 over Drainage Ditch in Sioux County, Iowa. It was built in 1976, so it is 49 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 6 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 5,200 vehicles a day, roughly 16% of them trucks, projected to reach 5,200 by 2042. The structure is 32 ft (9.8 m) long and 47 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

CarriesUS 18
CrossesDrainage Ditch
Location2.3 Mi. E of Jct. SR K52
RouteU.S. Route 18
StateIowa
Coordinates43.18599, -96.09147
Functional classRural Principal Arterial - Other

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.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36.8 US tons
Inventory rating28.2 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length32 ft (9.8 m)
Longest span10 ft (3 m)
Deck width47 ft (14.3 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,200 (2022)
Projected traffic5,200 by 2042
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 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 US 18 over Drainage Ditch built?

It was built in 1976, making it 49 years old in 2025.

What condition is US 18 over Drainage Ditch 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 March 2023.

How much traffic does US 18 over Drainage Ditch carry?

About 5,200 vehicles per day (2022 count), of which roughly 16% are trucks.

How long is US 18 over Drainage Ditch?

The structure is 32 ft (9.8 m) long with a longest span of 10 ft (3 m) and a deck 47 ft wide.

Who owns US 18 over Drainage Ditch?

It is owned by the State Highway Agency.