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3 ("Geologic Map of the San Francisco-San Jose Quadrangle", CDMG Map 5A, 1991). / Based on our explorations at this site, materials encountered are consistent with published soil and geologic mapping as described above. Soils encountered during our study are described as stiff and medium stiff, medium and low plastic, clay, silty clay and clayey silt to the maximum explored depth of about 25-ft. 7.0 PERCOLATION TESTING Three percolation test holes were excavated using 6.0 inch diameter flight auger using a Simco 2800 drill rig on February 4, 2014. Percolation tests were located within the proposed leach field area. Preliminary percolation testing was performed on February 11, 2014 and one of the test holes (P-3) was used for testing observed by the San Joaquin Environmental Health Department (SJEHD) on 2/12/14. The location of that test (P-3) is shown on the attached "Exploration Map" (Figure 2) and percolation test data is included in Appendix B. The percolation tests were performed within a 6.0-inch diameter test hole excavated to a depth of about 44-inches. Drain pipe (4-inch diameter, perforated within the lowermost 6-inches) was placed within the hole to prevent the sides of the hole from sloughing. A 2-inch layer of pea gravel was placed at the base of the hole to limit disturbance at the base of the hole. The holes were pre-saturated by adding 6-inches of clean water 24 hours prior to testing. The percolation tests were performed in general conformance with "Test Method #1" (SJEHD, Document 42-01-002, Revised 8-23-2011); the last 30-minutes of testing was observed by Ted Tasiopoulos, a registered Environmental Health Specialist, from the SJEHD. A copy of our field percolation test results, signed by a representative from SJCEHD, is provided in Appendix B. Results of the test are shown in the table below: TEST NI3NUM ft's R =p IItCQLATIONIRA3TE`06M_ P-3 1 3.5 1 480 8.0 DISCUSSION AND CONCLUSIONS Per SJEHD a suitable soil condition for use of a conventional septic/leach trench sewage disposal system, the soil stratum should be capable of percolating water at a rate o '6 minutes per inch (min/inch) at a depth of up to 3.5 feet below existing site grade or 30 min/inch for deepe sts. CTE's percolation test results for this project indicate a percolation rate pf 480 m inch at a depth of 3.5 feet. Based on above, the soil conditions at the site are not considered suitable for a conventional septic/leach trench sewage disposal system in accordance with SJEHD criteria. An engineered sewage disposal system is expected to be required and should be RIVERSIDE I VENTURA I MERGED I TRACY I SACRAMENTO I PALM SPRINGS I LANCASTER GEOTECHNICAL I ENVIRONMENTAL I CONSTRUCTION INSPECTION AND TESTING I CIVIL ENGINEERING I SURVEYING