The City operates multiple stormwater conveyance systems that discharge into the Portland Harbor Superfund Site in the lower Willamette River. Drainage areas for these systems include industrial, commercial, residential, and municipal properties, as well as open space. Some types of land uses can contribute chemicals to stormwater runoff, which discharges to the Willamette River.
GSI helped the City implement a stormwater source investigation program to identify and address stormwater issues on properties within its stormwater basins. Working closely with City staff and the Oregon Department of Environmental Quality, GSI helped identify properties that contribute unacceptable contamination to the City’s stormwater conveyance system. GSI provided technical support to ensure that problems at the identified properties were properly documented and plans were developed to control contaminant releases to the City’s stormwater system. This source control investigation work has helped regulators identify what source control actions (best management practices and engineering retrofits) are needed at upland sites.
GSI’s work has involved:
A City-owned outfall underneath the Vera Katz Eastbank Esplanade
A City outfall
A stormwater sampling site near the St. Johns Bridge