US Bridges

STC3756;DEER Flat over High Line Canal

Fair

Canyon County, Idaho · 5.2 S. 1.2 W. Nampa · Structure no. 000000000027405

Built
1990
35 years old
Condition
Fair
inspected March 2021
Type
Frame
Concrete
Length
63 ft
1 main span
Daily traffic
940
2023 count
Owner
Local
Other Local Agency

About this bridge

STC3756;DEER Flat over High Line Canal is a concrete frame carrying STC3756;DEER Flat over High Line Canal in Canyon County, Idaho. It was built in 1990, so it is 35 years old, younger than the Idaho average of 45.3 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 940 vehicles a day, roughly 1% of them trucks, projected to reach 1,410 by 2042. The structure is 63 ft (19.2 m) long and 49 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesSTC3756;DEER Flat
CrossesHigh Line Canal
Location5.2 S. 1.2 W. Nampa
RouteCounty Highway 3756
CountyCanyon County
StateIdaho
Coordinates43.50289, -116.585
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating82 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length63 ft (19.2 m)
Longest span63 ft (19.2 m)
Deck width49 ft (15 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic940 (2023)
Projected traffic1,410 by 2042
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther Local Agency
Maintained byOther Local Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$683,000 (2021 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was STC3756;DEER Flat over High Line Canal built?

It was built in 1990, making it 35 years old in 2025.

What condition is STC3756;DEER Flat over High Line Canal 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 2021.

How much traffic does STC3756;DEER Flat over High Line Canal carry?

About 940 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is STC3756;DEER Flat over High Line Canal?

The structure is 63 ft (19.2 m) long with a longest span of 63 ft (19.2 m) and a deck 49 ft wide.

Who owns STC3756;DEER Flat over High Line Canal?

It is owned by the Other Local Agency.