An estimated 153 million gal of rainwater falls along the six miles of I-5 in Everett, Wash., annually. The runoff has washed untreated into the Snohomish River for nearly 40 years, leaving Possession Sound clogged with oils, bits of rubber and various other highway pollutants.
As a part of the state's $263 million ongoing I-5 widening project, this water will now be treated before it is released back into the river, according to Washington Department of Transportation Project Director Mike Cotten.
Washington officials have installed four water treatment plants along under-construction stretches of highway. One of these treatment plants, in collaboration with the city of Everett, features a series of wetlands, and the planting of native vegetation is planned for next spring.
"It's a truly wonderful facility," said Dave Davis, director of engineering for Everett. "It complements the city's interest and vision for the riverfront area."
The city invested in this project to turn what would have been simply a bridge into a pedestrian bridge and aqueduct, Cotten said.
Washington state law mandates that when new lanes are added to a state highway rainwater draining from the road must be treated before it is released, according to Cotten. The Everett I-5 widening project, which will add new carpool lanes from the Boeing Freeway to the Snohomish River and merging lanes between U.S. 2 and 41st Street Southeast, is scheduled to finish as early as February.
