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II GEOTECHNICAL <br /> NEIL O. ANDERSON II ENVIRONMENTAL <br /> A N D A S S 'O C I A T E S INSPECTIONS & TESTING <br /> I <br /> LABORATORY SERVICES I <br /> POOL ENGINEERING <br /> POST TENSION DESIGN <br />' April 7, 2006 <br /> NOA Project Number:E05144BE I V) <br /> Send via U.S. Mail and Fax: (209) 464-0138, 6-pages <br /> APR <br /> 7 2006 <br /> I Rodney Estrada ENVIRONMENT HEALTH <br /> San Joaquin County Environmental Health Department PERMIT: p <br /> 304 E. Weber Avenue r�. 1V�CES <br /> Stockton, CA 95212 <br /> Re: 2°d Addendum Letter for the Segura Property-SSS/NLS <br /> 24195 South Cabe Road, Tracy, Calfornia <br /> Dear Rodney, <br /> To date, a Soil Suitability and Nitrate Loading Study dated March 16, 2006, as well as an <br /> Addendum letter dated April 3, 2006 have been submitted to your office for review. The <br /> Addendum letter corrected an erroneous calculation regarding the benefit of using a modified <br /> filter bed system. <br /> On April 6"and 7t'', we discussed over the phone that the nitrate loading method used by our <br /> office, which is largely based on the Hantzshe and Finnemore Equation, probably over-estimates <br /> the impact to the site due to the conservative nature of the method and variables used. We are <br /> aware that your office prefers this conservative approach. An example of the conservative nature <br /> of the variables is that second dwelling units (SDU) is always considered in the analysis,though <br /> it may not always be constructed on the property. Our approach also assumes the primary and <br /> SDU will have full occupancy over the long term. This may not be the situation over the long <br /> term as the equation is designed to estimate. <br /> - We are both aware-that the Tracy-area-is-susceptible-to-ieaching-nitrogerrimpacrs from septic` <br /> system leach fields, agricultural fertilizers, and dairies due to the shallow depth of ground water <br /> and moderately permeable soils. Nitrate impacts within the shallow and deeper portions of the <br /> aquifer outlying Tracy are not uncommon. <br /> During our conversation, I offered to reexamine the assumptions our office typically uses for <br /> nitrate loading projects and provide another scenario, based on real numbers;which may be <br /> considered for project approval. <br /> � The Hantzshe and Finnemore paper which introduces the equation uses 150 gallons per day per <br /> dwelling unit as an example. You indicated that your department considers 150 gpd per dwelling <br /> LODI ■ SACRAMENTO ■ MODESTO <br /> ENVIRONMENTAL DIVISION 902 Industrial Way,Lodi,California 95240 ■209.367.3701 ■ 209.369.4228 fax ■www.noanderson.com <br />