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WPCF Headworks Replacement Project Scope of Work <br />21 <br /> <br />Activities/Approach <br /> Project Administration and Coordination: HWA will manage geotechnical tasks, initiate and <br />maintain billing and invoicing over the 24-month project duration, and participate in biweekly <br />virtual coordination meetings with the design team to ensure consistent communication and <br />progress tracking. <br /> Environmental Document Review and Risk Assessment: HWA will review environmental <br />documents and evaluate potential geoenvironmental risks that may affect construction, <br />summarizing findings in the geotechnical report. <br /> Geotechnical Field Explorations Phase 1: HWA will plan and conduct site reconnaissance, <br />utility locates, and up to eight geotechnical borings with SCPT testing, groundwater <br />monitoring, and geoenvironmental sampling to inform design and contamination risk. The <br />Phase 1 exploration work includes the following activities: <br />o Preliminary Data Collection and Site Reconnaissance: HWA will gather existing <br />geotechnical data and conduct site visits to assess surface conditions and existing <br />structures. <br />o Exploration Planning and Utility Coordination: HWA will develop a detailed Phase 1 <br />exploration plan, including utility locates and clearance verification, and prepare a <br />memorandum outlining logistics, locations, and permitting needs. <br />o Subsurface Investigations and Monitoring: HWA will perform up to eight geotechnical <br />borings and SCPT investigations to evaluate soil and groundwater conditions, install <br />monitoring wells and piezometers, and deploy transducers for long-term groundwater <br />level tracking. <br />o Geoenvironmental Sampling and Analysis: HWA will collect and analyze soil and <br />groundwater samples from boring locations to identify potential contaminants, using EPA <br />and Ecology-approved methods. <br />o Data Processing and Reporting: All findings from fieldwork and lab analyses will be <br />compiled to support the preliminary design phase, including contamination screening, <br />subsurface characterization, and liquefaction potential assessment. <br /> Geotechnical Field Explorations - Phase 2: HWA will plan and complete geotechnical field <br />explorations in support of the intermediate design. This work will primarily focus on <br />hydrogeologic investigations and includes the following activities: <br />o Site Reconnaissance and Exploration Planning: HWA will conduct field visits to assess <br />surface conditions and coordinate with the design team to plan installation of <br />observation and pumping wells, supported by a detailed subsurface exploration <br />memorandum. <br />o Field Execution and Data Collection: HWA will perform utility locates, develop a <br />subsurface investigation plan, drill up to four borings, install and develop wells, and <br />collect soil samples for laboratory testing to evaluate subsurface conditions. <br />o Aquifer Testing and Reporting: HWA will conduct step and constant-rate aquifer pumping <br />tests, analyze hydrogeologic data, and prepare a report summarizing aquifer <br />characteristics to support design decisions. <br /> Geotechnical Engineering Analysis and Reporting, including the following activities: <br />o Subsurface Data Evaluation: HWA will analyze field and lab data to estimate soil strength <br />and other geotechnical properties critical to evaluating site conditions and proposed <br />improvements.