Old 99W over Glenn Valley Slough Oflo
GoodColusa County, California · 1.9 MI North of Haas RD · Structure no. 15C0088
- Built
- 1914
- 111 years old, rebuilt 1930
- Condition
- Good
- inspected July 2023
- Type
- Culvert
- Concrete Continuous
- Length
- 25 ft
- 3 main spans
- Daily traffic
- 1,298
- 2014 count
- Owner
- County
- County Highway Agency
About this bridge
Old 99W over Glenn Valley Slough Oflo is a concrete continuous culvert carrying Old 99W over Glenn Valley Slough Oflo in Colusa County, California. It was built in 1914 and reconstructed in 1930, so it is 111 years old, older than the California average of 54.8 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 1,298 vehicles a day, roughly 10% of them trucks, projected to reach 2,509 by 2041. The structure is 25 ft (7.6 m) long. If it were closed, the detour would be 6.2 mi (10 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Channel and channel protection | 8 Very Good | No problems noted. |
| Culvert | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Old 99W over Glenn Valley Slough Oflo built?
It was built in 1914, making it 111 years old in 2025. It was reconstructed in 1930.
What condition is Old 99W over Glenn Valley Slough Oflo 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 July 2023.
How much traffic does Old 99W over Glenn Valley Slough Oflo carry?
About 1,298 vehicles per day (2014 count), of which roughly 10% are trucks.
How long is Old 99W over Glenn Valley Slough Oflo?
The structure is 25 ft (7.6 m) long with a longest span of 8 ft (2.3 m).
Who owns Old 99W over Glenn Valley Slough Oflo?
It is owned by the County Highway Agency.