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_ Mr. Skibo July 9, 2004 Page 8 Y 6.2 Boring Preparation and Specifications On Parcel 1, the shallow boring was advanced to 3.09 feet. The deep boring was advanced to 15 feet and backfilled to 13.75 feet. On Parcel 2, the shallow boring was advanced to 3.54 feet. The deep boring was advanced to 25 feet, but backfill reduced the depth of the test hole to 24.22 feet. All four borings were drilled using a truck-mounted B-53 auger rig on June 17, 2004. A 2-inch diameter PVC pipe with perforations on the bottom was used to measure the drop of water in the percolation test boring. Approximately 2 inches of"pea gravel' were placed in the bottom of the boring, then the PVC pipe was installed on top of the gravel. Several feet of"pea gravel" were backfilled in the annular space. 6.3 Presaturation of Borings Presaturation of the percolation test holes occurred on June 17, 2004. The depth of water used to presoak was 12 inches above the bottom of the borings. After the 24-hour soak period, the presaturated holes were found to be intact on June 18, 2004. //6.4 Percolation Test Procedure and Results Four percolation tests were performed on June 18, 2004. The percolation tests were conducted in accordance with the requirements of San Joaquin County EHD. The last half hour of each percolation test was observed by Ms. Lisa Medina, Senior Registered �- Environmental Health Inspector, EHD. Measurement of the water level during the percolation test was from a fixed reference point on the PVC casing using an electric well sounder with an depth accuracy of 1/100th foot. All values on the field data sheet (appendix) are in decimal feet unless otherwise noted. After water drop was observed, the holes were checked for refill. The refill level is 6 inches of water above the bottom level of the percolation test hole. The readings were taken approximately every 30-minutes for the 4-hour duration tests. According the EHD Sewage Standards, each percolation test failed to achieve a satisfactory percolation rate. On Parcel 1 (P-1), both the shallow and deep percolation test failed due to little to no movement of the water. On Parcel l (P-2), the shallow percolation test failed with a percolation rate of 63 min/in; the deep percolation test achieved a an unsatisfactory percolation rate of 250 min/in. A summary of the percolation tests is presented in Table 5.