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i June 3, 2004 NOA Project Number: E04049A 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 i Presaturation of the percolation test holes occurred on May 19 and May 27, 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 May 20 and May 28, 2004. The deep holes were found to be dry, while the shallow holes were found to have standing water. 6.4 Percolation Test Procedure and Results ` The four 4-hour percolation tests were conducted on May 20 and May 28, 2004 in accordance Lwith the requirements of San Joaquin County EHD. The last half hour of the first two 4- hour percolation tests was observed by Mr. Ray Borges, Senior Registered Environmental Health Inspector, EHD. The last half hour of the second two 4-hour percolation tests was observed by Mr. Michael Escotto, 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 I 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. A satisfactory percolation rate for a deep (greater than 3.5-foot deep) test is 30 min/in or less, Land a satisfactory rate for a shallow (3-3.5 foot deep) test is 60 min/in or less. In the Phase I septic disposal area (P-1), the shallow percolation test failed due to no movement of the water, but the deep percolation test achieved a satisfactory percolation rate of 16.7 min/in. In the Phase H septic disposal area (P-2), the shallow percolation test failed with a percolation rate of 250 min/in, but the deep percolation test achieved a satisfactory Lpercolation rate of 22.7 min/in. A summary of the percolation tests is presented in Table 5. L E 10 "04 i L