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<br />COE will provide to G&E copies of prior soils testing (in particular soil resistivity data). <br />At some facility locations, COE may have previously conducted soils testing for seismic <br />evaluations (such as geotechnical borings, CPTs, etc.). COE will provide G&E copies of those <br />tests / reports. <br /> <br />After review, G&E will indicate to the City whether additional soil testing is suitable, and if so, <br />that testing and assessment will be performed by an on-call COE contractor. <br /> <br />After review of the distribution pipe system data (GIS maps, leak history), G&E will recommend <br />whether or not it is worthwhile to conduct a series of soil resistivity tests in the City of Everett. <br />This would be done by an on-call COE contractor, likely using Wenner 4-point tests. The results <br />of this testing will be the soil resistivity (Rho, measured in ohm-cm) at various locations <br />throughout the City. Soils with high resistivity (Rho over 5,000 ohm-cm) are generally not <br />aggressive to buried metal pipe (cast iron, steel, wrought iron, etc.). Soils with low resistivity <br />(Rho under 1,500 ohm-cm) are especially aggressive to buried metal pipe. The concept here is <br />that past pipe leak history may be correlated with soil resistivity; and that under earthquake <br />conditions, the relative weakness of existing buried pipes will also be so-correlated. <br /> <br />Task 2. Hazard Assessment <br /> <br />The City wishes this Vulnerability Assessment to reflect all hazards, including earthquakes, <br />volcanic eruption, tsunami, flood, landslide and other natural phenomena; as well as manmade <br />hazards. For the current work, the characterization of these hazards will be set as the same as that <br />previously established in the 2012 Vulnerability assessment, updated to reflect current (year <br />2023) information. It is considered that earthquakes will likely control the assessment and the <br />bulk of the effort will be to consider earthquakes. The new information includes: <br /> <br />• Earthquake ground motions will be based on NGA13 ground motion prediction equations <br />(GMPEs). These GMPE models were established in 2013. <br />• Updated tsunami inundation hazard assessment for the Puget Sound and Snohomish <br />River if available <br />• New hazard information reports prepared by third parties for the City and shared with <br />G&E. <br />• Liquefaction and landslide and fault offset (South Whidbey Island fault zone). We will <br />re-use the approaches to quantify these hazards as previously used in the 2012 effort. <br />Should refinement of these hazards be suitable for materially refining the findings of the <br />present Vulnerability Assessment, we will provide a recommendation for possible local <br />subsurface investigations. However, in order to minimize the cost for the present <br />Vulnerability Assessment, the strategy is to re-use available information, and factor in the <br />cost for local subsurface investigations as part of actual future mitigation work. <br /> <br />Task 3. Risk Assessment <br /> <br />Transmission System. We will update the risk assessment of the various transmission system <br />facilities, to reflect the mitigation work conducted by the City in the past decade or so. For