Project Description

RGI was retained by Roystone on Queen Ann, LLC (Roystone) to perform environmental and geotechnical services at the property located at 631 Queen Anne Avenue North in Seattle, Washington (hereafter referred to as the Property).
The Property is part of a larger Site identified by the Washington Department of Ecology (Ecology) as the Texaco 21157 Monterey Site. The Site consists of several properties and is bounded by West Roy Street to the north, Queen Anne Avenue North to the east, and 2nd Avenue West to the west. From 1927 through 1993 the Property was occupied by several gasoline service stations and automotive repair facilities, which resulted in numerous petroleum releases to soil and groundwater, which impacted several properties associated with the Site.
A number of remedial technologies were historically implemented at the Property including operation of a soil vapor extraction (SVE) system, a spray aeration vacuum extraction (SAVE) system, a dual phase extraction (DPE) system and light non-aqueous phase liquid (LNAPL) removal. However, a significant amount of petroleum impacted soil and groundwater remained on the Property after remediation was completed.
Beginning in 2017, RGI conducted several environmental investigations at the Property, which consisted of the following:
 A comprehensive review of previous investigations and historical information for the Property;
 Completed a geophysical survey;
 Completed several subsurface investigations, which consisted of collecting and analyzing soil and groundwater samples, and installation and sampling of groundwater monitoring wells. This required closure of the Trolley line along Queen Anne Avenue N and acquiring the necessary permits. Data obtained from these investigations was used to characterize the nature and extent of soil and groundwater impacts on- and off-Property, and
 Developed a plan for remediating soil and groundwater on the Property in conjunction with the construction of a mixed-use multi story building with an underground parking garage. Previous investigations and the plan for remediation were presented in the Interim Action Work Plan (IAWP) dated August 20, 2019, which was reviewed and approved by Ecology.
On August 29, 2019 Roystone, Chevron Environmental Management Company (CEMC) and Ecology entered into Agreed Order No 16537. Under AO 16537, Roystone and CEMC have designated lead roles for work associated with the cleanup of the Site. Roystone is responsible for the cleanup of the portion of the Site situated within the Property boundaries and the cleanup of the remainder of the Site, outside the Property boundaries, is the responsibility of CEMC.
In 2020, RGI collaborated with Ecology to implement the Interim Action (IA) described in the IAWP in conjunction with the redevelopment of the Property and in accordance with AO No. 16357. The IA consisted of the following tasks:
 Decommissioning of eight groundwater monitoring wells on the Property;
 Decommissioning, UST Site Assessment, and removal of three underground storage tanks (USTs), an oil water separator (OWS), two hoists, product piping, and dispenser islands. The decommissioning of USTs, product piping and dispenser islands was completed in accordance with WAC 173-360A and documented in the UST Site Assessment Report dated October 1, 2020;
 Directed excavation of test pits and collected and analyzed soil samples in order to strategically plan the remedial excavation and minimize interference with redevelopment activities;
 Completed direct push drilling at the northeastern portion of the Property in order to characterize the extent of soil contamination in this location where it was necessary to offset the shoring in order to protect the integrity of a utility pole. Soil analytical data was used to direct remedial excavation of contaminated soil in this location and immediately backfill the excavation with controlled density fill (CDF).
 Directed the remedial excavation and subsequent disposal of all contaminated soil situated within the Property boundaries to depths ranging from approximately 8’ bgs to 32’ below ground surface (bgs). Since the shoring wall were offset from the Property line by a few feet, it was necessary to excavate the area behind the shoring walls up to the Property boundary and backfill the area between the shoring wall and the Property boundary with CDF.
 Coordinated disposal of approximately 16,745 tons of petroleum impacted soil and 62.5 tons of tetrachloroethene (PCE) and trichloroethene (TCE) impacted soil classified as F002 hazardous waste;