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Page 2 P-6803 • Geotechnical analyses of the collected data; and • Preparation of this summary letter. PROPOSED CONSTRUCTION 'Che Grading Plan by UE indicates the 2.45-acre site will be subdivided to create three residential lots, a public street along [he northern boundary and an enlargement of the existing private driveway to serve the three new lots. Moderate grading operations are proposed to create the new home lots and roadways. The grading will consist of cuts up to about 6 feet deep and fills up to 13 feet thick. Various slopes adjacent to the homes will be created by the grading; these slopes will be up to 25 feet high and have inclinations of about 2:1 (horizontal to vertical). It should be noted little grading will be performed on Lot 1 (where an existing house is present) other than demolishing the current structure and building a new home. KE INVESTIGATION As indicated by KE, the property is somewhat trapezoidal in shape with maximum plan dimensions of approximately 560 feet long and 260 feet wide. It is bounded by residential properties on all sides. "I'he southern end of the parcel is relatively level (where the existing home is present on the proposed Lot 1) and generally slopes downhill m a northwesterly direction over the remainder of the site. A small, relatively level pad is located near the northwest corner. KE dnlled three exploratory borings, one on each of the proposed lots, hour to five feet of till was encountered in the existing pad areas where the Lot 1 and 3 homes will be built, and KE indicates up to 8 feet of fill could be present on Lot 3. KE generally encountered still clays and dense sands below the till. Their laboratory tests indicated the near-surface soils have a moderate expansion potential. KE concluded the only significant geotechmcal concern was the presence of existing undocumented till and recommended all such till be excavated and recompacted. KE recommended a keyway be excavated during the grading operations to support the fill buttress along Lots 2 and 3. They also recommended footing foundations be used for the proposed homes, and provided other gcotechnical recommendations for grading, slabs-on-grade and drainage. OUR EVALUATION We visited the site, examined a stereo pair of 1949 aerial photographs, and reviewed published geologic maps (see references at end). Our comments are as follows: "The absence of well-documented citations within the text of the report makes review of the opinions and conclusions presented in the report difficult. No references are provided for published regional geologic and hazard maps that cover the site. "Phew regional maps are not cued and no information is provided m the report on the geologic and tectonic setting, or regarding geologic deposits mapped in the vicinity of the site. In addition, no references are cited supporting the absence of active faulting across the site (e.g. the 'geologic references' mentioned m Section 4.1). No references or citations are provided for the hazard maps specifically reviewed as part of evaluation of liquefaction potential or landslide hazard (e.g. Sections 4.2.1 or 4.2.2). Only incomplete references are provided for Table 1. Inclusion of a separate references section that fully documents the maps, published reports, and aerial photographs reviewed in the preparation of the report would he useful for comparison with the references used by this reviewer m evaluation of the conclusions presented in the report.