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City of Everett, Public Works Operations <br /> November 13, 2020 Project No. 200505 <br /> Scope of Work <br /> Our proposed scope of work includes the following tasks: <br /> 1. Review of available operational data from the dredge contractor and previous sampling <br /> performed by the City. <br /> 2. Geotechnical engineering assessment of the landfill's lake-side berm. <br /> 3. Sampling and geotechnical laboratory testing and engineering property characterization of <br /> existing dredged backwash solids within the landfill. <br /> 4. Update of operational documents for the landfill. <br /> 5. Additional on-call services. <br /> 6. Project management. <br /> Task 1 - Review of Available Data <br /> As dredging and cleaning of the backwash settling pond is performed by a third-party contractor, <br /> Aspect will review available data collected by the contractor or the City during previous dredging <br /> processes. This will include review of quantities for the following items (if available): <br /> • Annual removed quantity (tons or cubic yards)of dredged material <br /> • Annual polymer flocculant addition records <br /> • Moisture content of the dredge following contractor dewatering <br /> In addition, we will review any other available data the City has from previous sampling events <br /> since the previous document updates. Data from this review will be used to support the deliverables <br /> outlined in subsequent tasks. As such,no deliverable will be provided for this Task 1. <br /> Task 2 - Geotechnical Assessment of the Landfill Lake Side <br /> Berm <br /> Based on your comments and concerns during our meeting and on the site walk, a geotechnical <br /> engineering assessment of the existing lake-side berm and access roadway is needed. It is believed <br /> the berm is comprised of a gravel cap and up to 10 feet of dredged sediment,built over steeply <br /> sloping(down toward Lake Chaplain)native glacial outwash(dense sand and gravel). As the <br /> landfill continues to be filled,there is some question as to whether the lateral surcharge might <br /> destabilize the be►tnhoadway. <br /> Work performed under this task will include oversight and documentation of up to four <br /> geotechnical test pits to be excavated within the berm with an excavator and operator provided by <br /> the City. The purpose of these test pits will be to determine the extent of dredged soils within the <br /> berm located between the landfill and the reservoir(southwest of the landfill),to assess impacts to <br /> landfill stability during filling and long-term stability. <br /> Page 2 <br />