US Bridges

170 Rd. over South Cottonwood River

PoorPosted for load

Marion County, Kansas · 1.5S 4.1W of Hillsboro · Structure no. 000570825905320

Built
1920
105 years old
Condition
Poor
inspected December 2024
Type
Culvert
Concrete
Length
31 ft
2 main spans
Daily traffic
20
2020 count
Owner
County
County Highway Agency

About this bridge

170 Rd. over South Cottonwood River is a concrete culvert carrying 170 Rd. over South Cottonwood River in Marion County, Kansas. It was built in 1920, so it is 105 years old, older than the Kansas average of 52.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 3 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. Its operating status is: posted for load restriction.

It carries about 20 vehicles a day, projected to reach 25 by 2044. The structure is 31 ft (9.4 m) long and 18 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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Carries170 Rd.
CrossesSouth Cottonwood River
Location1.5S 4.1W of Hillsboro
RouteCounty Highway 0
CountyMarion County
StateKansas
Coordinates38.31881, -97.28092
Functional classRural Local

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
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Culvert3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Last inspectionDecember 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry8: Equal to present desirable criteria
Waterway adequacy3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating13.9 US tons
Inventory rating6.9 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadUnknown
Structure length31 ft (9.4 m)
Longest span15 ft (4.6 m)
Deck width18 ft (5.5 m)
Roadway width16 ft (4.8 m)
Vertical clearance over deck100 ft (30.5 m)

Traffic and service

Average daily traffic20 (2020)
Projected traffic25 by 2044
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$250,000
NavigationNo navigation control on waterway

Frequently asked questions

When was 170 Rd. over South Cottonwood River built?

It was built in 1920, making it 105 years old in 2025.

What condition is 170 Rd. over South Cottonwood River 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 December 2024.

How much traffic does 170 Rd. over South Cottonwood River carry?

About 20 vehicles per day (2020 count).

How long is 170 Rd. over South Cottonwood River?

The structure is 31 ft (9.4 m) long with a longest span of 15 ft (4.6 m) and a deck 18 ft wide.

Who owns 170 Rd. over South Cottonwood River?

It is owned by the County Highway Agency.