Background

River Mile 11 East (RM 11E) of the Lower Willamette River is the upstream-most SMA of the PHSS. A Group of five PRPs is carrying out an Administrative Order on Consent (AOC) to perform focused FS and Design work to ready RM 11E for remedial action. Foth was retained in 2013 to provide subject matter expert services to one of the PRPs as the AOC is performed by the Group. Over this timeframe, Foth has provided highly valued input into the preparation of an Implementability Study, Recontamination Assessment, and presently, a Basis of Design Report (BODR).

RM11E is the most upstream SMA in the PHSS and the RM 11E Group has been performing focused FS work since 2013. As a result RM11E has more sediment characterization information that most other SMAs in the PHSS. The Agencies are looking to RM11E to be one of the first SMAs to complete remedial design and commence remedial action. The shoreline of RM11E includes two operating terminals, Glacier NW and Cargill’s Irving Terminal. The vitality of these operations requires a well thought out remedial design to minimize disruption to their operations during remedial action. Also in RM 11E, a utility company, PacifiCorp, has a major power line crossing located close to the surface, causing concern for damage during remedial action implementation. Several City of Portland storm sewers outfalls, including one CSO, discharge into RM 11E. Upland source control work is being performed by the RM 11E PRPs under review of ODEQ as a precursor to moving into final design and implementation of remedial action. Recontamination potential, and implementability of capping or dredging, are key challenges due to potential upland soil erosion and over-steepened river bank slopes. Pile structures of active shipping terminal docks are numerous in the SMA shoreline area where impacted sediments will need to be addressed.

Results

Through the focused FS work, Recontamination Assessment, Implementability Study and now the BODR, Foth has worked with the PRP Group to focus on key implementability issues for our client’s site to avoid unnecessary investigation and detailed evaluation of alternatives with little to no feasibility. Foth has also inserted investigation and design ideas that were successful on other sites across the country, based on our lessons learned, but not considered in USEPA Region 10. Foth has used statistical methods to help identify additional sample locations for better sediment characterization and has effectively reduced the modeled impacted sediment footprint for the RM 11E Site. Foth has worked collaboratively and has an excellent working relationship with all of the RM 11E PRP Group members, the Group’s lead consultant, the individual Group members’ consultants and attorneys, ODEQ and USEPA.