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E1 9 r Soil Suitability&Nitrate Loading Study Page 9 St. Patrick's Church, Escalon, CA {�a Project No. 607.1 1 October 14, 2609 6.0 PERCOLATION TEST North American Technical Service NQS}-£rrst co d a percolation test on August 20, 2009 with additional to on October 9, 2009 u er the supervision Fill of the San Joaquin County Environmenta nt and using EHD guidelines. The agency defines a shallow percolation test as between 36 and 42 E inches, while a deep percolation test is between 42 inches and 25 feet. In this case, a shallow test was initially deemed appropriate by the agency, but later deeper test was requested. A test pea=csl� i rate of less th �-60 inutes per inch for a shallow test, or less than 30 nutes per inch for a deep test is I considered a "passed" test, meanie at a tantard--d-6sign septic system is acceptable. The test is to be made within e 'footprint"* the proposed new leach Meld.F! Es 6.1 Test Description F On August 18, 2009 a 6-inch diameter soil boring was advanced to a depth of 42 inches using truck-mounted drilling equipment owned and operated by NATS. + ,An approximately 2-inch thick layer of "pea-gravel" was placed at the bottom of -! the boring, and a 4-inch diameter PVC temporary casing perforated at the bottom was place over the gravel pad. The annulus between the casing and the boring was then partially filled with pea-gravel. The PVC casing was used to measure the decreasing water level in the boring. In the 24 hours prior to completing the test, the boring was pre-soaked. The ' packed boringwas filled with water to a depth of 12 inches. p The percolation test was completed in accordance with EHD requirements and under the supervision an EHD representative on August 19, 2009. The duration of the test was four hours. An electronic well sounder with an accuracy of 0.01 feet was used to monitor the fall of water during the test from a fixed point of reference. F! On October 9, 2009, a second, deeper test hole located near the site of the test boring was the subject of a percolation test. In addition, two borings at the F site of the proposed large septic system in the southwest part of the parcel were also tested. The test methods used were similar to that described for the August t 6.2 Test Results The first percolation test conducted on August 19 yielded a percolation rate of 83.3 minutes per inch. This compares with the minimum acceptable rate of 60 Fi minutes per inch for a standard-design septic system. The soil at the site of the 1 2937 Veneman Ave.,#$240 Geo-Phase Environmental Inc. Phone: (209) 569.0293 Modesto, CA 95356 Eak: (209) 569-0295 F1 E