For commuters who use Lake Washington Boulevard Northeast, the southern section will be detoured for a month this summer as the city replaces old culverts used by Cochran Springs.

After July 4, drivers will be detoured from Lake Washington Boulevard onto Northup Way or Northeast 38th Place. The intent of the $1.6 million project is to unclog a section of Cochran Springs, which runs from Watershed Park in the Houghton Neighborhood to Yarrow Bay, where it goes through several culverts under Lake Washington Boulevard by Interstate 520.

According to Neighborhood Services Coordinator Christian Knight, the culverts have collected so much sediment that it leaves only a few inches for water to pass through, which has led to flooding as well as inhibited the fish who swim through the springs. The city’s plan is to replace the two culverts with a single boxed culvert that will be rectangular instead of circular.

The problem first came to the city’s attention when businesses near Yarrow Bay were having flooding problems due to the clogged culverts, according to Knight.

The boulevard handles average traffic of 20,000 cars every day in both directions, Knight said, compared to 85th Street, which sees 44,000 vehicles a day.