Remedial Action, Hamilton-Labree Roads Groundwater Contamination Superfund Site, OU-1

As subcontractor to AECOM, Brice supported an innovative remedial action project at Berwick Creek in Chehalis, Washington. The project objective was to remediate PCE contamination in the subsurface beneath Berwick Creek using thermal treatment. The source of contamination was dumping of spent solvent. Brice’s scope of work included site preparation, temporary facilities, Berwick Creek water management; temporary creek diversion; excavation, transportation and disposal; groundwater dewatering; installation of a vapor plenum/insulating concrete cap; and site restoration.

In accordance with the design, Brice installed a protective insulating plenum layer/vapor cap over the in situ thermal remediation (ISTR) surface area and under the creek bed as an isolation layer and vapor recovery system to the thermal remediation occurring below the creek. This approach removed/disposed of contaminated creek bed sediments and bank soil at the start of construction in this area, eliminating the potential requirement to remove this material following ISTR if ISTR did not adequately treat the creek bed sediment and bank soil. By temporarily segregating the stream flow, excavating the impacted sediment/shallow soil, installing a three-sided (open top) channel in the current creek alignment, returning the flow back into the open channel, the construction footprint was minimized and addressed the potential flood events without modifying the floodplain elevations, maintained creek conditions adequate for fish habitat, and protected the stream water from heat and contamination during ISTR operations.

Brice was faced with multiple challenges including design changes in the field, complex site conditions requiring vigilance including working in and around power lines with cranes, coordinating with as many as 27 stakeholders, increased safety measures to avoid electrification during thermal operations performed under a waterway, and the unique balancing act of maintaining the correct water temperature to ensure the health of the fish habitat during thermal remediation operations.