Big Flat Road over Tennison Creek
FairWashington County, Idaho · 11.8 S. 11.0 E. Midvale · Structure no. 000000000028920
- Built
- 1930
- 95 years old, rebuilt 2004
- Condition
- Fair
- inspected June 2024
- Type
- Stringer/Multi-beam or Girder
- Steel
- Length
- 23 ft
- 1 main span
- Daily traffic
- 50
- 2023 count
- Owner
- County
- County Highway Agency
About this bridge
Big Flat Road over Tennison Creek is a steel stringer/multi-beam or girder carrying Big Flat Road over Tennison Creek in Washington County, Idaho. It was built in 1930 and reconstructed in 2004, so it is 95 years old, older 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 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 50 vehicles a day, roughly 10% of them trucks, projected to reach 75 by 2039. The structure is 23 ft (7 m) long and 20 ft wide. If it were closed, the detour would be 18 mi (29 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Big Flat Road over Tennison Creek built?
It was built in 1930, making it 95 years old in 2025. It was reconstructed in 2004.
What condition is Big Flat Road over Tennison Creek 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 June 2024.
How much traffic does Big Flat Road over Tennison Creek carry?
About 50 vehicles per day (2023 count), of which roughly 10% are trucks.
How long is Big Flat Road over Tennison Creek?
The structure is 23 ft (7 m) long with a longest span of 22 ft (6.7 m) and a deck 20 ft wide.
Who owns Big Flat Road over Tennison Creek?
It is owned by the County Highway Agency.