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SAN LEANDRO GENERAL PLAN UPDATE FINAL EIR <br />CITY OF SAN LEANDRO <br />COMMENTS AND RESPONSES <br />PLACEWORKS 5-17 <br />TABLE 5-1 COMMENTS AND RESPONSE MATRIX <br />Comment # Date Comment Response <br />requirements are a comprehensive approach to regulating new development, and <br />include extensive provisions for addressing geologic and soil stability issues on <br />development sites, which could result from seismic activity and other causes as well <br />(see Impacts GEO-3 and GEO-4 in the Draft EIR). The Draft General Plan also carries <br />forward existing Action EH.1.1.A, which requires soils and/or geologic reports for <br />development in areas of serious risk, such as liquefaction hazard areas. As <br />previously discussed in Response B04-02, exposure of people or structures to <br />seismic hazards due to project implementation is no longer considered a CEQA <br />impact. Seismic hazards are nevertheless an important land use issue for the City. <br />Through its existing policy and regulatory requirements, the City acknowledges the <br />fact of seismic-related land stability issues such as liquefaction and expansive soils, <br />and has in place a means to engineer for those constraints in new development. All <br />of these requirements are existing, and proposed to be carried forward in the <br />proposed San Leandro 2035 General Plan. Through Draft General Plan Policy EH-1.4, <br />the City also commits to revising and updating “construction codes and regulations <br />to incorporate the latest available information and technology related to <br />eqrthquake…hazards” (Draft General Plan page7-45). The Draft EIR adequaltely <br />addresses land stability issues and no further discussion is required. <br />B04-05 <br /> <br />I even found a 1990's study by the San Francisco Bay Regional Water Quality Control <br />Board Groundwater Committee which contains maps showing the 1000 feet of bay <br />sediments that underlie the Marina area with two aquifers that could be impacted. It <br />even mentions the shallow landfill gas plume (methane is the predominant green house <br />gas) under the golf course. Anybody who smells the gases vented from the two 5 foot in <br />diameter out-gassing vents in Oyster Bay on warm afternoons can tell you what <br />puncturing that would smell like; it would certainly affect Air Quality. Could driving piles <br />into the highest aquifer (down to 250 feet) affect what is known as the San Leandro toxic <br />groundwater plume (mostly from old leaking gas wells) from farther east and impact the <br />many San Leandro Waste Water Treatment Plant wells which go from 50 to 750 feet? <br />The presence of Bay Mud is noted in Section 4.5.1.2 of the Draft EIR and on the soils <br />map in Figure 4.5-2. Page 4.7-1 of the Draft EIR further identifies four major <br />groundwater plumes in the city that are undergoing site characterization and/or <br />remediation. The Shoreline project EIR states that the nearest of these plumes is 0.4 <br />miles from the Shoreline project site, and further notes that construction vibration <br />effects tend to dissipate quickly, within 500 to 600 feet of the source. Therefore it is <br />not likely that construction vibration from any pile driving would affect the <br />groundwater plume. In any case, as noted in earlier responses, the Draft General <br />Plan does not change the existing Shoreline site land use designations that were <br />approved in 2015; nor does the Draft General Plan approve development on this or <br />any other site in the city. Concerns noted by the commenter specific to individual <br />development projects do not have to be analyzed in the context of the adoption <br />and implementation of the proposed San Leandro 2035 General Plan and Zoning <br />Code amendments. <br />B04-06 <br /> <br />According to the California Building Code the two most prominent methods of mitigation <br />for liquefaction are the driving of piles and piers and soil replacement. These will have <br />negative significant impacts far beyond geology, soil and water, including surface and <br />subtidal biology, air quality, noise and traffic - most certainly during the construction <br />phase. <br />The City agrees that pile driving and soil replacement can be mitigation for <br />liquefaction, but these techniques will not be proposed or appropriate for all <br />development projects. The comment reflects the importance of choosing <br />engineering techniques tailored to a particular development site. As noted in earlier <br />responses, the City’s grading regulations require development projects to prepare <br />soils reports that not only assess soils conditions, such as liquefaction, but also <br />identify corrective actions for soils stability conditions. Furthermore, the City may <br />condition a grading permit to have the work performed in a particular manner. In <br />those cases where pile driving is proposed, the City will evaluate the proposal