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Page 13 of 59 <br />City of Everett Merrill & Ring Bridge Replacement <br />3.3.5 Conduct Phase 2 Explorations (Slope Reconnaissance): HWA will conduct a two-day <br />slope reconnaissance of the steep slopes along the ravine adjacent to the bridge. This <br />reconnaissance will be used to identify critical slope features, obvious signs of slope <br />instability and to map exposed soil outcroppings. Hand borings and Dynamic Cone <br />Penetrometer (DCP) testing will be completed along the steep slopes during the <br />reconnaissance to quantify the thickness of loose, near surface colluvial soils along the <br />slopes. Information from the slope reconnaissance will be critical in the design of slope <br />protection measures. <br />In addition to the two-day slope reconnaissance, HWA will conduct two days of drilling <br />within the ravine with a limited access drill rig. Limited access borings will be drilled at <br />locations of possible retaining walls or areas of observed slope instability. Limited <br />access borings will be drilled to depths ranging from 15 to 25 feet below ground surface, <br />or until practical refusal, whichever occurs first. No groundwater monitoring wells will <br />be installed within the limited access borings; however, depth to groundwater at the time <br />of drilling (if observed) will be noted. <br />3.3.6 Generate Boring logs and Assign Laboratory Testing: HWA will prepare summary <br />boring logs and perform laboratory testing to evaluate relevant physical properties of the <br />site soils. Laboratory testing would include moisture content, grain-size distribution, <br />Atterberg Limits, and direct shear testing. <br />3.3.7 Groundwater Monitoring: HWA shall install a groundwater monitoring transducer in <br />both of the proposed monitoring wells. These transducers will be set to acquire <br />groundwater elevation readings every half an hour for the duration of 6 months. A <br />geologic representative from HWA shall make two site visits to download and process <br />the groundwater data. This data will be used to provide geotechnical design <br />recommendations and to provide prospective contractors with an accurate representation <br />of the seasonal groundwater variations across the site. <br />3.4 Geo Environmental Support <br />3.4.1 Review of Existing/Readily Available Data: HWA will review environmental regulatory <br />database records, historical documentation, and regulatory agency files (if deemed <br />necessary) to assess sites of concern, particularly those located adjacent to the project <br />corridor, that have the potential for hazardous materials impacts to the project. The data <br />review will be completed per WSDOT “right-sized” Hazardous Materials Analysis report <br />guidance. Historical information reviewed will include Sanborn Fire Insurance maps, <br />historical aerial photos, historical topographic maps and historical city directories for the <br />streets included in the project corridor. <br />3.4.2 Site Reconnaissance: HWA will complete a site reconnaissance from public rights-of- <br />way or publicly accessible properties (i.e., windshield survey).