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The soil in the boring was similar to that described by the Soil Survey. Topsoil was encountered to approximately three feet below ground surface, followed by hardpan to 12 feet below ground surface, followed by sand to the full depth of the hole, according to the Armstrong report. It is apparent from a percolation test permit on file at the San Joaquin County Environmental Health Department that Armstrong also conducted a shallow percolation test in a similar area of the Site in September 1994; the boring was advanced to a depth of 3.5 feet (Appendix 4). Discussion of Soil Lithology Based on the soil described in the boring, there appears to be limited potential for percolation in the shallow soil zone, but moderate potential in the deep zone. Sandy soils generally have a much greater potential for percolation than fine-grained or cemented soils. However, a percolation test is the only accepted method for determining the suitability of the soils for a septic disposal area. Percolation test results are discussed in the following section. Percolation Test Armstrong conducted a shallow percolation test in September of 1994 and a deep percolation test on January 5, 1995. The soil borings discussed above were used for the percolation test holes. Percolation Test Procedure A percolation test sheet was not available for the shallow test. A percolation rate of three-quarters of an inch per 30 minutes (40 minutes per inch, min/in) was recorded by Armstrong for the shallow test. For the deep percolation test, Armstrong completed a four-hour test. Water level measurements were taken every 30 minutes during the four-hour period. The test form was signed by Greg Olivera, Registered Environmental Health Specialist at the San Joaquin County Environmental Health Division (Appendix 4). Based on a final water drop of 3.5 inches, Armstrong determined that the percolation rate for the deep boring was 7 inches per hour (equivalent to 8.6 min/in). Per San Joaquin County Environmental Health Department's definition, a shallow percolation test hole has a depth between 36 and 42 inches; a satisfactory percolation rate for a shallow test is greater than or equal to 1 minute per inch (min/in) but less than or equal to 60 min/in drop. A deep percolation test hole has a depth between 3.5 and 25 feet; a satisfactory percolation rate for a deep test is greater than or equal to 1 minute per inch (min/in) but less than or equal to 30 min/in drop. For the Site to utilize a LOGE 1931 Page 6