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�'- <br /> ,ra - <br /> GEOTECHNICAL. <br /> NEIL O. ANDERSON ENVIRONMENTAL <br /> A N D A S SOC I A T E S INSPECTIONS & TESTING <br /> s <br /> LABORATORY SERVICES <br /> POOL ENG=INEERING <br /> POST TENSION DESIGN <br /> I <br /> September 27, 2007 �C <br /> Project Number: E07109A �' LE) <br /> Mr. Rodney Estrada SEP 2 8 2007 <br /> San Joaquin County Environmental Health Department ENVIRONMENT HEALTH <br /> 600 E. Main Street PERMIT/SERVICES <br /> Stockton CA 95202 <br /> Subject: Nitrate Loading Study Addendum Letter 0 I a <br /> 5555 West Grant Line Road 'V <br /> Tracy, California <br /> Dear Rodney, <br /> Per your request, this letter addresses several questions regarding a nitrate loading calculation <br /> our office completed for the subject site. As you may recall, Kleinfelder & Associates, Stockton <br /> office, completed a full nitrate loading study (NLS) for the subject site. Your office found their <br /> study incomplete. <br /> Our office was contracted to perform a percolation test and layout of a septic system for the <br /> facility. Mike Huggins of your office requested that we perform an analysis using our best <br /> judgment to determine whether the facility could potentially cause a buildup of nitrate in the <br /> shallow ground water over the long term above 10 mg/L-N. Our report, dated August 22, <br /> 2007 (Our job no. E07109A), indicated that we predict a build up of to 9.9 mg/L-N. This <br /> estimate used a conservative rain fall number of 3.27 inches. <br /> You requested that we use an Nw number of 80 mg/L-N and wanted clarification for the <br /> background nitrate concentration for rainfall. Using an Nw value of 80 mg/L-N would result in <br /> 12 mg/L-N for our previous analysis. To clarify this issue, an Nw value of 80 mg/L-N was <br /> substituted into the Kleinfelder analysis which also used a Nb value of 0.5 mg/L-N and updated <br /> the calculation with the correct flow and acreage for the site discussed in our report dated <br /> August 22, 2007. If an Nw value of 80 mg/L-N were used using Kleinfelder's variables for rain <br /> amount and concentration and leach field denitrification, the result would be 6.9 mg/-N, well <br /> below the cutoff of 10 mg/L-N. <br /> ANGELS CAMP • LODI MODESTO • RENO • SACRAMENTO WALNUT CREEK <br /> L 0 D 1 902 Industrial Way Lodi,CA 95240 • 209.367.3701 • FAX 209-369.4228 www.noanderson.com <br />