Structure 18610B0000000 · Wahkiakum County, WA
Carries SR 4 over Tide Gate Culvert, 29.4 E Jct SR 401.
A culvert 21 ft across. Lengths are drawn to scale; at this length a semi-truck would be a speck. Each part is colored by its latest inspection rating. The inventory records lengths but not heights, so those are drawn as typical for a culvert.
| State | Washington |
| County | Wahkiakum |
| Location | 29.4 E Jct SR 401 |
| Carries | SR 4 |
| Crosses | Tide Gate Culvert |
| Coordinates | 46.22360, -123.39267 |
| Material | Concrete |
| Design | Culvert |
| Total Length | 21.0 ft (6.4 m) |
| Max Span | 21.0 ft (6.4 m) |
| Deck Area | 76.2 sq m |
| Main Spans | 1 |
| Year Built | 2015 |
| Avg Daily Traffic | 2,084 (2023) |
| Truck Traffic | 12% |
| Lanes On Bridge | 2 |
| Last Inspection | August 2023 |
| Inspection Frequency | Every 24 months |
| Owner | State Highway Agency |
| Historical Significance | Historical significance is not determined |
| Scour Critical | 8 — Stable, low risk |
| Structure Number | 0018610B0000000 |
Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."
A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.