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April 20, 2004 NOA Project Number: E04002A F Page 9/ . ►/ 6.2 Boring Preparation and Specifications F1Four soil borings were advanced on the Site.-Two shallow borings were advanced to 3.11 and. 3:20 feet by hand auguring on April-4.5, 2044. .On-e deep boring was drilled to 8.70 feet on April 15, 2004 using a truck-mounted Deep Rock auger.rig: The second deep boring was drilled to 25F1 'F -- feet on April 19,-2004 using a truck-mounted B,53;rig; after the boring was measured it was found to be 24 feet due to sloughing._. - -_ 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 open soil boring, then the PVC pipe was installed on top of the gravel.-Several feet = of"pea gravel' w—ere -in the annular space. 6.3 Presaturation of-Borings- -Presaturation of the-percolation test holes occurred on April 192004._The depth of water used to pre-soak was .12 inchesabovethe.bottom of the borings. After the 24-hour soak period, the presaturated holes were found-to be intact and dry on April-20; 2004. 6.4 Percolation Test Procedure and-Results _ A percolation test was conducted for,all the borings on April 20,`2004 in accordance with the. requirements of-the EHD. A percolation test with duration of 4 hours was performed. The last half hour of the 4-hour percolation tests was observed by IVIS. Lisa Medina, Environmental - ..y Health Inspector,EHD. 1 1 =x 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 11100th-foot. A114_ F! tabulated.values ori the field data sheet(appendix) are in decimal feet. After water drop was observed, the holes were checked for:refill.=The refill-level.was approximately 0.5 ft (6 inches) of water above the bottom level of the percolation test liole. The readings were takenF1 _ approximately every 30 minutes for a period of 4 hours: A shallow percolation test is defined by the EHD as-being between 36 and 42 inches in depth. A t deep percolation test is defin=ed as being between 42 inches and 25 feet in depth. A satisfactory percolation rate for a shallow test is less than or equal to 60 minutes per inch drop. A satisfactory percolation rate for a deep test is-less than or equal to 30 minutes per inch drop. Either one shallow or deep test must demonstrate a satisfactory percolation rate within the proposed septic system disposal field. A summary of the percolation tests is presented in Table F1} 5' _ _.