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Stantec August 6,2019 Page 6 of 14 conditions at the site are anticipated to generally consist of interbedded alluvial deposits, including near surface soft fine-grained silt,clay and organic soils, overlying medium dense to dense sands. Fill is present over portions of the site. Liquefaction risk within the alluvial sands underlying the site is mapped as moderate to high. The geotechnical desktop assessment will be based on review of existing subsurface soil and groundwater data at the site and within the site vicinity,through publicly available records as well as data provided by the City(i.e.existing geotechnical reports,conditions assessments,design and as-built records associated with plant infrastructure, and settlement observations or monitoring data). We anticipate that sufficient information will be available to support a high-level preliminary assessment of the following potential vulnerabilities: • Potential for ongoing settlement of infrastructure due to consolidation settlement of the fine- grained surficial clay,silt or organic soils, due to loading associated with shallow foundations and existing(or proposed)site fills. • Preliminary assessment of liquefaction risk under current seismic hazard levels and associated anticipated performance (deflections) of existing critical infrastructure under seismic loading. Critical infrastructure would include buildings, pipelines, levees,etc. as applicable. • The vulnerability of the plant infrastructure to climate change and sea level rise impact will involve an assessment of the existing levee system. Levee performance under future sea level/flood elevations can be assessed considering the levee design geometry and cross section, subsurface profile and existing crest elevation profile. The preliminary assessment will identify levee sections potentially at risk of overtopping, under-seepage,or erosion under existing or future elevated flood levels. The results of the geotechnical desktop assessment will assist to identify existing deficiencies, recommended improvements,and inform capital planning related to future plant upgrades. Subtask 300.005 Condition/Resiliency Improvements Stantec will summarize the findings of this condition assessment and recommend near-term improvements, modifications or upgrades to address deficiencies currently affecting, or with the potential to affect, performance and capacity of the Facility. For critical issues(those which must be addressed in the next five years),the team will assess two improvement options: • Interim Upgrades(Near-term): improvements that provide reliable near-term functioning without significantly upgrading remaining useful life • Investment Upgrades(Long-term):improvements that allow the facility to function reliably as a long-term WPCF asset As the complete facility improvement options are evaluated,this information will be used to determine whether near-term expenditures should be included to address critical reliability needs that will not be addressed in the initial phase of plant improvements. Stantec will prepare a TM summarizing the results of this condition assessment and conduct a 3-hour workshop to review the findings of these assessments with City staff and discuss prioritization recommendations for both near and long-term investment.These will be included, ultimately, in the CIP