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Lisa Medina <br /> December 29,2003 <br /> Page 2 <br /> • Section 3.7: Expected maximum use is explained in the report. The average daily flow <br /> remains 149 gallons. Two (2) employees and 30 customers. <br /> • Section 4.2: The use of septic systems in the area are a potential off site source of nitrate <br /> contamination of ground water. No other nitrate/nitrogen generating uses were <br /> recognized. The site is vacant. There are no dairies, agriculture, or septic uses on the site. <br /> • Section 6.1: See attached Wong Engineers site plan with annotations. <br /> • Section 6.3: A percolation test was performed in a new location. The location is noted on <br /> the attached site plan by Wong Engineers. The percolation test form is attached to this <br /> letter. The percolation test was conducted according to EHD requirements. <br /> • Section 6.4: See below <br /> Percolation Test Boring Locations <br /> A"shallow" and "deep"percolation test was conducted in a location designated for a <br /> sewage disposal system. Refer to the scaled site plan by Wong Engineers for the exact <br /> location (attached). <br /> Boring Preparation and Specifications <br /> The shallow borings were advanced to 3.15 feet and the deep borings were drilled to 22.4 <br /> feet below the ground surface. The deep boring was drilled using a 4-inch diameter <br /> truck-mounted Deep Rock auger rig. The shallow boring was drilled using a 4-inch <br /> diameter hand auger drilling tool. <br /> A 2-inch diameter PVC pipe with perforations on the bottom was used to measure the <br /> drop of water in the percolation test boring. Approximately 2 inches of"pea gravel"were <br /> placed in the bottom of the open soil boring, then the PVC pipe was installed on top of <br /> the gravel. Several feet of"pea gravel'were backfilled in the annular space. <br /> Presaturation of Borings <br /> Presaturation of the percolation test holes occurred on December 17, 2003. The depth of <br /> water used to pre-soak was 12 inches above the bottom of the borings. After the 24-hour <br /> soak period, the presaturated holes were found to be intact and dry on December 18, <br /> 2003. <br /> Percolation Test Procedure and Results <br /> A percolation test was conducted for all the borings on December 18, 2003 in accordance <br /> with the requirements of San Joaquin County EHD. A percolation test with duration of 4 <br /> hours was performed due to the presence of fine grained soils. The last half hour of the 4- <br /> ?pERSO <br /> t 'Y <br /> Z W <br /> O � <br /> 9SS O��r <br />