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Commissioner Arkin stated that he would like to see an analysis with data that shows two years /"" of rainfall at 150% above the average. Discussion ensued regarding this recommendation and alternative options. Ms. Kline suggested that the Planning Commission direct the applicant to commence taking the measures of the long-term wells currently on the property, so that at the time of the submittal of a PUD the applicant could provide information regarding the effect of rainfall on the groundwater table. Commissioner Arkin stated that he would like to have the amount of earthquake movement reflected at different data points in the analysis. Mr. Grubstick advised that the consultants could run something beyond the maximum credible earthquake movement. He commented on the potential design criteria that could be applied to the site. He suggested the following wording: "analyze an energy release that exceeds the maximum creditable earthquake by 20%." Mr. Roush suggested that this language be added as a mitigation measure, and that the modified language be brought back to the Planning Commission for review. He noted that the Planning Commission could recommend the certification of the SEIR subject to the Commission reviewing the clarification of the mitigation measures. - Commissioner Roberts moved to recommend: (1) certification of the final Supplemental Environmental Impact Report for Oak Tree Farm - Phase 3, with language to be reviewed by the Planning Commission concerning the following: . For future PUD applications a biological survey shall be prepared and submitted for review to the u.s. Fish and Wildlife Service. . An analysis of the groundwater table using two years of data based on 150% "above the normal" rainfall for this area shall be prepared in order to determine whether there are any stability problems. The data may include prior years, but prior to grading in the hillside area, the analysis is to include data for the next two winters. . An analysis on earth movement shall be prepared utilizing data that exceeds the maximum credible earthquake. and (2) removal of the geotechnical setback line (Berlogar line), and the application of the geotechnical recommendations and mitigations contained in the FSEIR and related documents for all future development within the area currently within the geotechnical setback area of the Oak Tree Farm subdivision. Commissioner Arkin seconded the motion. Commissioner Harvey suggested that rather than say 150% of the rainfall, he would recommend the wording "2-1/2 standard deviations." Commissioner Roberts agreed to amend the motion to state "2-1/2 standard deviations" (or some other industry standard as researched by staff) rather than 150%. Commissioner Arkin seconded the amended motion. r- PLANNING COMMISSION MINUTES June 13,2001 Page 8