Lewis - Jackson Hwy S

Jackson Hwy S. was originally part of the Pacific Highway. The Pacific Highway was 1,687 miles long and stretched from the Mexican border to the Canadian border and in 1924, was the longest continuous stretch of paved road in the world. The Pacific Highway was completed in 1924, and in 1927, became US Highway 99. On July 1, 1964, US Highway 99 started to be phased out, as the construction of Interstate 5 was nearing completion. In 1968, the freeway was finished and US Highway 99 was decommissioned. In 1980 the state transferred title of the Section of US Highway 99 that is now known as Jackson Hwy S. to Lewis County.

The original culvert was a 3' diameter precast concrete pipe. The pipe had significant cracks running along the top and the bottom, had extensive section loss, and had the potential of collapsing. There was also scaling, spalling, and areas of efflorescence. The pipe ran through a concrete retaining wall at the intake end, there was a long drop to the plunge pool at the outfall end, and had a significant depth of cover also.

By replacing the culvert we eliminated the potential failure and collapse of the existing structure, and possibly Jackson Hwy S. itself. Due to permitting and environmental requirements, a fish passage culvert had to be installed. The original 3' diameter culvert was replaced with a 10' wide by 6' tall concrete split box culvert, and the stream was regraded to make it fish passable.