Cleaning up Portland Harbor is not only about in-water sediments. An important part of the process is identifying and controlling all the sources of contamination to river sediments. Contaminants can migrate from upland properties to river sediments via wastewater and stormwater discharges, spills, groundwater, riverbank erosion, overwater activities and air deposition. If the current and potential future sources of sediment contamination are not addressed the river sediments could be recontaminated after the cleanup.
There are over 400 outfall pipes in Portland Harbor. Most of them are owned by private parties while others are owned by public entities. In December 2011, the city completed a program to control all the combined sewer system outfalls. Domestic sewage is not the source of contaminants that persist in Portland Harbor, but controlling sewer overflows significantly improves Willamette River water quality. The combined sewer system, which once overflowed an average of 50 times a year, now overflows to the river only during extreme storm events.
To date, DEQ has identified more than 100 upland sites that may be potential sources of Portland Harbor contamination. The DEQ Voluntary Cleanup Program is addressing many of these sites. Go to http://www.deq.state.or.us/lq/cu/nwr/PortlandHarbor for more information on these efforts.
City of Portland staff is working closely with DEQ to ensure that cleanup sites that discharge to the city stormwater system also address potential stormwater contamination issues.
Investigating Stormwater from City Outfalls
Since the EPA designated Portland Harbor as a Superfund Site, the city's Bureau Environmental Services and Oregon DEQ have worked together to ensure that all significant contaminant sources to the city stormwater conveyance systems in the harbor are identified and referred to an appropriate city, state, or federal program for control. This targeted collaborative investigation, also known as the City Outfalls Project, was necessary because some sources required onsite investigation or remedial action that was beyond city regulatory authority.