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March 19,2004 `' NOA Project Number: E0415A Page 8 Percolation rate is one important measure of septic system applicability. Based on the percolation rate of the shallow soil zone—described later in the report—, the shallow soil zone has demonstrated a satisfactory percolation rate according to the San Joaquin County Environmental Health Department. A deep percolation test has demonstrated a satisfactory percolation rate. The utilization of seepage pits in conjunction with shallow leach lines should be utilized for the septic system disposal field. Since a shallow percolation test achieved a satisfactory percolation rate, the Site has met the L EHD requirement for a satisfactory percolation rate. Construction of the septic system should follow the,requirementsof the EHD Sewage Standards. 6.0 PERCOLATION TEST INFORMATION 6.1 Percolation Test Boring Locations One shallow and one deep percolation test were conducted within the area designated for a sewage disposal system. Please refer to the scaled site plan for the exact locations (Plate 1). 6.2 Boring Preparation and Specifications ` The shallow boring was advanced to 3.15 feet, and the deep boring was drilled to 22.15 feet. All four borings were drilled using a truck-mounted Deep Rock auger rig on March 15, 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 open soil 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 March 15, 2004. The depth of water used �. to pre-soak was 12 inches above the bottom of the borings. After the 24-hour soak period, the presaturated holes were found to be intact and dry on March 16, 2004. �•• 6.4 Percolation Test Procedure and Results A percolation test was conducted for all the borings on March 16, 2004 in accordance with the 6. 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 Mr. Justin Hess, Environmental Health Inspector, EHD.