SR 20 over Alder Creek
GoodSkagit County, Washington · 13.3 E JCT SR 9 · Structure no. 0003361A0000000
- Built
- 1948
- 77 years old
- Condition
- Good
- inspected March 2023
- Type
- Slab
- Concrete Continuous
- Length
- 82 ft
- 4 main spans
- Daily traffic
- 5,888
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
SR 20 over Alder Creek is a concrete continuous slab carrying SR 20 over Alder Creek in Skagit County, Washington. It was built in 1948, so it is 77 years old, older than the Washington average of 49.8 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 5,888 vehicles a day, roughly 8% of them trucks, projected to reach 8,631 by 2040. The structure is 82 ft (25 m) long and 40 ft wide. If it were closed, the detour would be 3.7 mi (6 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 |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| 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 SR 20 over Alder Creek built?
It was built in 1948, making it 77 years old in 2025.
What condition is SR 20 over Alder Creek 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 March 2023.
How much traffic does SR 20 over Alder Creek carry?
About 5,888 vehicles per day (2023 count), of which roughly 8% are trucks.
How long is SR 20 over Alder Creek?
The structure is 82 ft (25 m) long with a longest span of 19 ft (5.8 m) and a deck 40 ft wide.
Who owns SR 20 over Alder Creek?
It is owned by the State Highway Agency.