Portland's Green Streets: Lessons Learned Retrofitting our Urban Watersheds

The City of Portland, Bureau of Environmental Services (BES) uses green street facilities, a Low Impact Development technique, to manage stormwater in the urban watershed. Green street facilities have multiple benefits for our urban environments. They are effective in reducing peak flows and flow volume to solve combined sewer overflows and basement sewer backups. Green streets also filter pollutants, replenish groundwater, make attractive streetscapes for neighborhoods, and benefit pedestrian connections throughout our cities. Through design, construction, and monitoring of green street facilities, the City has collected a wide range of design details that have contributed to the success of the facilities. The paper will discuss the variety of constructed facilities in the "Green Street Toolbox" and their appropriate application as well as the range of elements critical to the design of a green street — neighborhood type or adjacent land use, water collection and inlet design, utility conflicts, parking considerations, check dams, lined facility design, traffic volumes, street type and use, pedestrian and bike improvements. Project examples will include built facilities in residential, commercial, and industrial areas of the City.