Memorandum <br />Date: October 27, 2017 <br />To: File <br />From: Teri Higgins <br />Subject: Clarification/Update to Ballantyne Consulting Technical Memo <br />During the final review of the Wastewater Master Plan, it was discovered that the current HazVu map <br />on the DOGAMI website indicates a significant amount of moderate liquefaction Hazard in the Eugene <br />Area. A review of data used for the Ballantyne memo, and a discussion with Don Ballantyne revealed <br />the following: <br />The source used for the analysis was the DOGAMI Open File Report 13-06 (O-13-06), which is the <br />file specific to the Cascadia M9 Event. This is the same source used to develop the Oregon <br />Resilience Plan. <br />The outline of the areas on the current HazVu map are identical to the outlines used for the <br />technical memo. <br />The current HazVu map indicates no areas of low probability of liquefaction, only None, Moderate, <br />or High in the Eugene area. <br />The attached map indicated the areas of low probability used for both the EWEB report and the <br />Eugene report. <br />Don confirmed that DOGAMI modified the current HazVu and changed most of the Low <br />Probability areas to Moderate. Although he is not exactly sure why they did that, he suspects <br />they were trying to standardize liquefaction across the state. <br />As stated in Don’s technical memo, he does not believe that the lower valleys of Eugene are of a <br />high enough probability for liquefaction to warrant concerns, and the need to change/upgrade <br />construction standards of gravity wastewater pipe. The recommendations outlined on page 12 <br />of the memo for areas of moderate probability should only be applied to areas in the hills of <br />south Eugene. <br />2020 Eugene Wastewater Master Plan Appendix A-14