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PGSF WMVD Storm and Combined Sewer Design Scope of Work 08-25-2023 <br /> <br />13 of 41 <br /> <br />Category 2: Sensitive information <br />Category 2: For official use only / disclosure permissible by law. <br />locations to assist with the dewatering requirements. <br />The geotechnical borings will also include chemical sampling to dispose of investigation <br />derived waste (IDW) from drilling activities. One soil sample and one reconnaissance <br />groundwater sample, collected from temporary wells installed during drilling, will be <br />submitted to an environmental analytical laboratory for analysis of potential contaminants of <br />concern (PCOC) based on general disposal facility requirements for properties within an <br />industrial area. The laboratory will analyze soil and/or groundwater samples for some, any, or <br />all of the following PCOC (based on preliminary data): <br />Analysis Method <br />Petroleum Hydrocarbons - gasoline NWTPH-Gx <br />Petroleum Hydrocarbons – diesel, oil NWTPH-Dx <br />RCRA 8 Metals (Ag, As, Ba, Cd, Cr, Hg, Pb & Se) EPA 6010D/6020B/7471B/200.7/200.8/7470A <br />Hexavalent Chromium SM 3500-Cr B <br />Volatile Organic Compounds (VOCs) EPA #8260D <br />Semivolatile Organic Compounds (SVOCs) with low level PAHs EPA #8270E/SIM <br />Polychlorinated biphenyls (PCBs) EPA #8082A <br />Toxicity Characteristic Leaching Procedure (TCLP) EPA 1311/1312 <br />All investigation derived waste (IDW; i.e., drilling spoils, purged groundwater, and drilling <br />decontamination water) will be drummed in steel 55-gallon drums and stored at a location <br />provided by the City that is in close proximity to the project area (i.e., less than 5 miles). The <br />IDW drums will be stored at the provided location until chemical laboratory testing has been <br />completed, the disposal facility approval has been obtained, and the IDW subcontractor has <br />removed the drums (potentially six weeks, or longer, from completion of drilling). IDW waste <br />profile documentation required for the disposal of the IDW will need to be signed by the City <br />or an authorized City representative. The provided IDW disposal estimate assumes that IDW <br />meets Subtitle D landfill criteria and is not considered a hazardous waste. If conditions are <br />encountered that do not meet this criteria, additional time to dispose of the drums and/or <br />expenses may be incurred. <br />All borings will be drilled within the Right-of-Way of City of Everett with the exception of one <br />boring to be located on City of Everett sewer easement located on Norton Terminal, owned by <br />the Port of Everett. All borings will be drilled using a track or truck mounted with Hollow Stem <br />Auger drilling equipment. <br />HWA assumed the above-mentioned geotechnical explorations will take approximately 5 <br />working days to complete and the work will require traffic control consisting of 2 flaggers to <br />conduct the necessary lane closures. <br />Each of the above-described geotechnical explorations will be logged by an HWA <br />geotechnical engineer geologist. <br />• Generate Exploration Logs and Assign Laboratory Testing: HWA will prepare summary boring <br />and core hole logs and perform laboratory testing to evaluate relevant physical properties of <br />select soil samples. Laboratory testing will include moisture content, grain-size distribution, <br />one dimensional consolidation, organic content, and Atterberg Limits. <br />• Conduct Groundwater Monitoring: HWA will install groundwater monitoring transducers in the <br />monitoring wells. The transducers will be set to take groundwater elevation readings every <br />half an hour for 1 year. HWA will make periodic site visits to download and process the <br />groundwater data. This data will be used to provide the designer and prospective contractors