Treating what nature provides

From ODOT-

On the Willamette River Bridge project, planning for the rainy season and the impacts of water runoff is very important.



The new wider southbound bridge has a larger surface area that will collect more rainwater than the old bridge did. The rainwater runoff becomes contaminated when it mixes with pollutants from vehicles, such as grease, brake dust, automotive fluids and deicing chemicals. Without containment and treatment, the runoff would flow directly into the river and nearby natural areas.



Instead, we have started collecting runoff and discharging it into a system of bioswales for treatment. Bioswales are landscape elements designed to remove silt and pollution from surface runoff. They are gently sloped areas planted with native vegetation. Runoff captured from the bridge is filtered by the vegetation or held in a grassy bowl until particles settle out. The treated water either soaks into the ground or is released into the surrounding watershed, such as the river or nearby creeks.



We have built multiple bioswales to treat rainwater runoff on or near the project site, saving the cost of collecting and piping it for discharge further away.



Building bioswales is just one of the ways ODOT is reducing the environmental footprint of the new Willamette River Bridge.