Green infrastructure takes many different forms, from street trees and concrete-curbed stormwater planters in the Tabor to the River area that serve one block, to large wetlands that capture and filter stormwater from large areas of development (like the Mason Flats project), and everything in between.
In some parts of Portland, stormwater flows down roadside ditches that carry the water to streams. During big rain storms, the ditches can carry sediment and other pollutants into the stream. As shown at the left, the road itself can also be eroded.
Improving these ditches to help slow and filter the water before it reaches the stream is one way the City is protecting water quality and habitat in local waterways. “Roadside swale” projects essentially turn ditches into long, linear rain gardens, and can add other community benefits as well.
Two of these green infrastructure projects are underway now in Southwest Portland:
- More than ½ mile of swales will be constructed along SW Stephenson Street between SW 35th Avenue and Boones Ferry Road, managing water before it reaches Tryon Creek. Two green street planters will also be constructed near Stephenson Elementary School.
- About 920 feet of swales will be constructed along SW Hamilton Street between SW 40th and 47th avenues, to manage water before it reaches Fanno Creek.
Construction will start this month to re-construct existing ditches into vegetated swales that will carry stormwater runoff and allow some runoff to soak into the ground as plants and shrubs filter pollutants.
Currently, many sections of the roads have little or no shoulder for pedestrian safety, like in the photo of SW Stephenson St. at right. So, the projects also include constructing a four-foot paved shoulder adjacent to the swales, which will increase pedestrian access and safety.
(concept drawing of new swale and road shoulder improvements)
Learn more about these projects, with maps and up-to-date construction information, on the project websites: