Portland uses green streets, ecoroofs, trees and other green infrastructure to slow stormwater runoff, reduce runoff volumes, protect water quality and improve overall watershed health. In addition, urban streams, forests, and wetlands manage stormwater naturally. When combined, this green stormwater infrastructure currently manages 51 percent of city-controlled impervious surfaces.
Green infrastructure has become a major component in the City’s overall stormwater management, as shown by the growing number of green streets treating runoff from Portland roadways. Projects that include green infrastructure elements are often less costly and include multiple benefits when compared to other alternatives. The Bureau of Environmental Services manages the city’s stormwater system.
Cumulative number of Citywide Green Street Features
The % for Green Program supports construction of green street facilities in the City of Portland that manage stormwater, enhance livability and provide other environmental benefits. Funds can be requested for green street facility projects in the public right-of-way or on private property, but must treat stormwater from the public right-of-way. Green street swales, curb extensions, planters, vegetated infiltration basins, porous paving and other sustainable stormwater facility types are eligible.
The Tabor to the River Program area covers about 2.3 square miles in southeast Portland. The program combines innovative stormwater management techniques with sewer repairs and improvements to solve a variety of urban challenges. The strength of this program is that it creates a partnership between the city and the community to develop sustainable solutions to our urban watershed problems in a more collaborative approach. The work helps reduce basement flooding, manages stormwater naturally and supports restoration of our watersheds.
Benefits also include overall cost savings. Resolving the sewer system problems in the Tabor to the River Program area with traditional pipe only solutions would have cost an estimated $144 million. Adding green infrastructure projects, like green streets, voluntary private property retrofits, tree planting and the enhancement of park and natural areas, reduces the estimated cost to $81 million and multiplies the benefits to the watershed and the community.
The CSO Cornerstone Projects implemented stormwater control measures in the first phase of the Combined Sewer Overflow Program. Located throughout north, east and southeast Portland, the projects installed 3,000 stormwater sumps and sedimentation manholes. These collect street runoff, trap sediment and allow water to soak into the ground. In some locations, the projects redirected stormwater out of the combined sewer and into new storm-only sewers. The separated stormwater then flowed into water quality treatment facilities like Ramsey Lake and the BES Water Pollution Control Lab pond before discharging to the river.