ARCHIVED REPORTS LEC APPLICATION FOR CERTIFICATION

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■ No large reservoirs are located in the site vicinity,however smaller reservoirs are located adjacent to the site. Based on the size, impounded water quantity, and risk due to overtopping of these nearby reservoirs,the potential of flooding and erosion due to dam failure is low. The site is not located within close proximity to a levee,therefore the potential of flooding due to levee failure is low. ■ Data provided by Environmental Data Resources, Inc. indicates the site lies within a FEMA designated 100-year flood zone. However, a civil engineer should confirm the flood zone designation. ■ Based on the inland location of the site,the potential for damage from tsunamis or seiches is low. Phase 3 improvements to the White Slough Water Pollution Control Facility Mitigated Negative Declaration states seiche and tsunami waves would not be a threat to the site (West Yost Associates,2007). ■ Preliminary bearing capacity evaluations indicate the bearing capacity of the onsite soils will be on the order of 2,500 pounds per square foot and 4,000 psf with an over-excavation and recompaction of 5 feet, similar to the adjacent site. This value should not be used for design purposes and should be re-evaluated and additional recommendations made as part of the design level geotechnical investigations for the site. ■ All excavations and grading should conform to the 2007 California Building Code (CBC). Cuts and trenches in unconsolidated alluvial deposits may require special dewatering, sloping, and shoring considerations during design. 4.9 RECOMMENDATIONS The primary constraint for site development is the potential for liquefaction and subsequent differential settlements. It is anticipated that zones of liquefiable soils will be limited to isolated pockets of loose, near-surface, sandy soils. A more detailed study of the liquefaction potential as well as estimation of settlements associated with liquefaction, are recommended as part of the design-level geotechnical investigations for future development at the site. Based on the results of this further investigation, recommendations to reduce the potential for damage associated with seismically induced settlements will be made. It is anticipated over-excavation of approximately 5 feet and recompaction as engineered fill will reduce the risk of damage to structures from differential settlement associated with liquefaction to tolerable levels. Recommendation for the extent of over-excavation and compaction characteristics of the engineered fill should be provided in the design-level geotechnical report. Based on shear wave velocities encountered during our subsurface investigation, it is anticipated excavations can largely be accomplished with conventional heavy equipment such as a CAT D8 dozer. Near surface cemented soils were encountered during our subsurface exploration, and by Kleinfelder for the adjacent site, that may result in somewhat slower excavation. Additional investigations which should be performed as part of the design level geotechnical investigations include a more detailed evaluation of the expansion and collapsibility potential of subsurface materials. Based on reviewed reference documents,damage potential to proposed structures due to expansive or collapsible soils is anticipated to be low. It is anticipated the risk of damage to structures from expansive or collapsible soils will be reduced to tolerable levels by over-excavating and recompacting the top 5 feet of soil onsite,as previously discussed. Ground shaking caused by earthquake activity of faults in the general vicinity is possible and likely to occur. Appropriate structural design to mitigate the effect of anticipated ground shaking should be conducted according to applicable standards of practice,codes,and regulations. Project No.5593-01-05 C A A LT O 7/29/2008 10 Engineering Inc . NCPA GFS.doc