2600 FEDERAL AVE 2021 PORT OF EVERETT 2025-09-29

Substantive Requirements Review Landau Associates Figures 4 and 5 show the approximate location and distribution of compressible wood waste deposits at the locations of the identified cross sections. Sections A-A' and C-C' present the estimated extent of wood waste in the northern half of the site; Section B-B' presents the estimated extent of wood waste in the southern half of the site. During its initial review of site subsurface data, LAI identified localized wood waste deposits in the southern half of the site. Previous investigations, completed by others (Moffat & Nichol 2014), indicate that many of the original site structures that occupied the site were supported on deep foundations, consisting primarily of steel H-piles and timber piles. Auger cast piles, steel pipe piles, and pre-cast concrete piles also may have been used to support some of the original structures. These structures have been removed from the site; however, many of the original foundation elements were left in place. Abandoned piles and other foundation elements, especially H-piles and concrete pile caps, are present throughout the site, especially in the northeast corner. K-C has completed recent interim action cleanup excavations that have uncovered the tops of pile foundations (Figure 6). LAI understands that where encountered, K-C surveyed the approximate top elevations and horizontal extents of remnant foundations prior to backfilling the cleanup excavations. 2.1.3 Groundwater Conditions The results of previous site investigations completed by others (Shannon &Wilson 2014) indicate that groundwater levels vary from east to west. Toward the eastern edge of the site, groundwater is anticipated to be present at approximately 1 to 4 ft below ground surface (bgs); at the western edge of the site, groundwater is likely present at 6 to 12 ft bgs. During site visits in the fall of 2020, LAI observed groundwater conditions in excavations completed during the recent interim action cleanup. The groundwater conditions were consistent with those described in Shannon &Wilson's 2014 report. Groundwater levels along the western edge of the site may be tidally influenced by nearby Possession Sound and Port Gardner. When preparing the settlement estimates presented herein, LAI conservatively assumed a groundwater level of 10 ft bgs. The site grading history makes previously reported depths to groundwater uncertain because site grades may have changed since the depths to groundwater were measured. 2.2 Supplemental Geotechnical Data Collection To fill data gaps identified during its geotechnical and geologic review, LAI performed supplemental subsurface investigations at the site. Conditions observed during the supplemental investigations are described in the following sections. 2.2.1 Supplemental Borings LAI advanced eight hollow-stem auger borings (MIE-SB-1 through MIE-SB-8) on September 23 and 24, 2020 and two hollow-stem auger borings (MIE-SB-9 and MIE-SB-10) on April 14, 2021. The borings were advanced 26.5 to 31.5 ft bgs at the locations shown on Figure 2. LAI attempted to advance a Geotechnical Engineering Report 0121049.040.041 Norton Terminal Development&MTCA 3rd Interim Action 2-2 May 7,2021