BHC Consultants LLC Amendment 1 - Laserfiche WebLink

August 26, 2016 HWA Project No. 2016-P101-21 The third boring will be drilled in the grassy area behind the guard rail, near the northern most proposed manhole structure. This boring will also be within the WSDOT right of way and will be drilled with a track mounted drill rig. All exploration activities will be monitored full time by a HWA geotechnical engineer or geologist. We expect that drilling of the three (3)proposed borings and one (1)well install will take approximately 2 working days. • Generate Boring Logs and Conduct Laboratory Testing: All of the soil samples retrieved from our explorations will be sealed in plastic bags and taken to our Bothell, Washington laboratory for further examination and testing. Selected soil samples will be tested to determine relevant engineering and index properties for our engineering analyses. Soil and laboratory test information will be presented on summary boring logs that will be generated upon completion of our exploration program. • Groundwater Monitoring: HWA will make up to 3 site visits to collect groundwater readings from the transducer installed in the proposed monitoring well. Groundwater monitoring will be conducted for a period of 6 months from the installation of the well. • Develop Geologic Interpretation: HWA will construct a geologic profile across the proposed site based on the information obtained from the above described geotechnical borings. This profile will be provided in the geotechnical report and will be used for design calculations. Geotechnical Engineering This work will include the following subtasks. • Engineering Analysis: HWA will evaluate the data derived from our field investigations and laboratory testing to complete our engineering analysis. Our engineering analysis will include development of seismic design parameters, foundation design, uplift evaluations, dewatering analysis, temporary shoring earth pressures and permanent earth pressures. • Internal QA/QC: HWA will have all design calculations and recommendations reviewed by a senior principal prior to distribution to the design team or the CITY. • Geotechnical Engineering Report: HWA will generate a draft and final geotechnical engineering report that will contain the results of the geotechnical engineering investigation, including description of surface and subsurface conditions; a site plan showing exploration locations and other pertinent features; summary boring logs; and Snohomish River Overflow Structure R4