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SUBSURFACE SOIL STRUCTURE A Mobile Drill B-24 truck-mounted drill rig was used to drill the percolation test borings, and to retrieve soil samples from auger cuttings. A field log-of-boring was completed from the deep perc test boring, which is found on the EHD Perc Test Field Form, located in Appendix C. Soil \ characteristics are described using the Unified Soil Classification System(USCS). As denoted on the log of boring, the surface soil characteristics for the perc test boring underlying the Designated Remainder Parcel reveal the soil to be predominately a lean clay containing a fine- to-medium gravel, with a cemented silts hardpan and claypan. The surface soils are very slowly permeable with deeper soils much more permeable. The cemented, fine sandy silts hardpan continues down to approximately 3 feet. Below this stratum is a well-graded silty gravel down to 22 ft. From 22 ft to 25 ft is a lean, sandy clay. PERCOLATION TESTING r ' i On December 2, 2005, the pere test borings were drilled in the location on the Designated Remainder Parcel as depicted on the new Tentative Map. This location was chosen so that any future leachfield could be installed with a required distance from the on-site well. After drilling the shallow perc test boring,the sidewalls were scored with a pry-bar and the loose / material removed. Due to the encountered gravel strata, the deep boring was terminated at this (� depth. The 19.2 ft test boring could not be scored due to its depth. Two inches of pea gravel was placed at the bottom of each boring to prevent scour and three-inch perforated PVC pipe was inserted in both test borings. The test borings were pre-saturated on December 7, 2005 at 1230 hrs with 12 inches of clear water in accordance with EHD regulations. On December 8,2005, 0900 hrs,percolation testing commenced for both borings. Post-soak status for each test boring is illustrated in the Table below. Since standing water was measured in the shallow test boring, EHD Perc Test Procedure#1 was conducted for this test boring. No water remained in the deep boring,therefore, EHD Test Procedure#2 was conducted. The last half hour of the four-hour tests was witnessed by Ted Tasiopoulos, R.E.H.S. of the San Joaquin County Environmental Health Department. The following Table summarizes the proposed Parcel number, septic system structure to be installed based on depth of acceptable perc rates, Street Address, A.P.N. Number,post soak period status and percolation test results at the perc test depth: Page-2 �jj - Chesney Consulting