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CITY OF SANTA ANA <br />Planning and Building Agency <br />Project No.: D-6289-08 <br />St. Barbara Catholic School <br />Percolation -Infiltration Tests <br />Reduction Factor Method <br />Approved <br />FOR PERMIT ISSUANCE <br />Location <br />If without FS Using <br />(Reduction Factor <br />Method) <br />inch/hour <br />If wit lVAR—Er2 Using <br />(Red ction Factor <br />Method) <br />inch/hour <br />PC-1 <br />2.0426 <br />1.0213 <br />PC-2 <br />2.9388 <br />1.4694 <br />AVERAGE: <br />2.4907 <br />1.2453 <br />More than 0.3 inch per hour, thus PASSED, does meet the requirement. <br />Conclusions <br />The subgrade soils consist of generally alluvium consisting of medium dense to dense <br />silty sand to sand, gray in color and moist to very moist. <br />According to the field percolation test data and converting for infiltration Rate by using <br />Porchet Method and Reduction Factor Method, the values for infiltration rates were <br />found to be more than the allowed rate of 0.3 inch per hour in accordance with the <br />Orange County Technical Guidance Document and Low Impact Development <br />Stormwater Infiltration dated 12/20/2013. <br />However, the groundwater encountered during our field boring was at 14 feet depth and <br />the historical high groundwater in accordance with CGS was found to be about 5 feet and <br />in accordance with Orange County Technical Guidance Document, the infiltration basin <br />must be constructed at least 10 feet above the groundwater depth, hence it does not meet <br />the requirement. We recommend using other systems instead of BMP infiltration <br />retention basin system. <br />Additional Services <br />This office will be available for further consultation. <br />