On April 24, WSDOT closed State Route 510 at milepost 6.28 between Lacey and Nisqually following the discovery of a culvert failure. The culvert is located approximately 25 feet below the roadway surface. WSDOT hydraulic crews used small cameras and robots to inspect the culvert. They found the culvert had collapsed in several locations, allowing water to undermine the roadway, which allowed the highway to sink 5 inches. WSDOT issued an emergency declaration to help advance repairs and reopen the highway as quickly as possible.
Annual average daily traffic volumes for this section of SR 510 is 13,000.
WSDOT estimates nearly 1,500 state-owned culverts are about to or have reached the end of their useful life. Many culverts are more than 50 years old and need replacement. There is little maintenance crews can do at this point to prevent future failures.
When culverts fail, a ripple effect occurs to other parts of the roadway and transportation system. This runs the risk of more emergency road closures and lengthy detours that affect travel and commerce.
Final project cost will be updated later this spring.
There are no related maps and drawings.
