GSI has assisted the City of Portland in developing its project approaches, regulatory strategy, and source control strategies for the Portland Harbor Superfund Site.


In Portland, Oregon there is an 11-mile long reach of the lower Willamette River that has been designated by the EPA as the Portland Harbor Superfund site. More than a century of industrial facilities have operated along the river and historical discharges have led to contaminated sediments accumulating in the river.

In response to the area being designated as a superfund site, the City of Portland, as the owner of the public stormwater conveyance system, needed to develop project approaches, regulatory strategy, and a source control program.

GSI’s Solution

As part of its participation, the City needed to manage contamination from stormwater, so GSI gathered pertinent data from the City and other literature to estimate the significance of stormwater discharges to the Willamette River. To further refine our understanding, we managed a sediment sampling project in the downtown Portland area of the Willamette River. This work involved defining the stormwater system for each system basin, identifying potential upland sources of contamination within each basin, and identifying additional sediment sampling locations where more data was necessary. Using the data results our team estimated how stormwater affected the downtown area of the Willamette River.

Finally, based on the data we collected and analyzed, we helped the City develop source control strategies to eliminate the release of unacceptable contaminates to the stormwater systems that occur in the upland areas served by its stormwater systems.