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

Substantive Requirements Review Landau Associates extended to 20 ft bgs. The sand was underlain by loose sand with gravel and shells that extended to the maximum depth explored (31.5 ft bgs). Subsurface conditions in boring MIE-SB-7 were observed to consist of approximately 7.5 ft of medium dense sand with trace gravel and silt, underlain by approximately 2.5 ft of loose, silty sand with shells. Medium dense sand with trace gravel and wood was observed beneath the silty sand and extended to the maximum depth explored (31.5 ft bgs). Subsurface conditions in boring MIE-SB-8 were observed to consist of approximately 10 ft of loose, silty sand with trace gravel, underlain by approximately 10 ft of very loose to loose sand with trace gravel. Medium dense sand with gravel and trace silt was observed beneath the loose sand and extended to the maximum depth explored (31.5 ft bgs). Subsurface conditions in boring MIE-SB-9 were observed to consist of approximately 10.5 ft of medium dense sand with variable silt and gravel content, underlain by approximately 1.5 ft of stiff, sandy silt with shells. Medium dense sand with variable gravel and shell content was observed beneath the silt and extended to the maximum depth explored (31.5 ft bgs). Subsurface conditions in boring MIE-SB-10 were observed to consist of approximately 7.5 ft of medium dense sand with silt and trace gravel, underlain by approximately 24 ft of loose to medium dense sand with trace silt. The medium dense sand extended to the maximum depth explored (31.5 ft bgs).Upon completion of fieldwork, soil samples collected from the borings were transported to LAI's soils laboratory for further examination and testing. Laboratory test results are presented in Appendix B. 2.2.2 Electrical Resistivity Tomography Surveys Global Geophysics, LLC subcontracted by LAI, completed ERT surveys at the site. The ERT survey alignments are shown on Figure 7. The ERT technique involves transmitting an electrical current into the ground and measuring the received voltage to identify differences in the electrical properties of subsurface deposits. By calculating the resistivity of the subsurface deposit that the electrical current passes through, it is possible to infer the geologic makeup of the deposit. ERT data are compared with data gathered from subsurface explorations to develop site-specific correlations between soil resistivity and soil type. Typically, material with a very high moisture content, such as organic deposits, has a very low resistivity, whereas a mostly mineral soil has a higher resistivity. Survey results and a detailed description of the survey method are provided in Appendix C. The majority of wood waste deposits was observed in the northern half of the site; however, a large area and several smaller areas of wood waste deposits, were identified in the southern half of the site. The results of the ERT survey generally accord with existing site data and the subsurface conditions observed in LAI's September 2020 and April 2021 explorations. Geotechnical Engineering Report 0121049.040.041 Norton Terminal Development&MTCA 3rd Interim Action 2-4 May 7,2021