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March 10, 2020 Irer con <br /> Mr. Greg Soares <br /> 28484 Lemon Avenue <br /> Escalon, CA 95320 <br /> P: (209) 992-0130 <br /> E: jr(cDamstephens.net <br /> Re: Soil Suitability Study/ Nitrate Loading Study Addendum <br /> Soares Property, APN: APN 249-110-23 <br /> 28484 Lemon Avenue 1ZECEIVED <br /> Escalon, San Joaquin County, California <br /> Terracon Project No. NA197095 MAR 10 202-0 <br /> Dear Mr. Soares, ENVIRONMENTAL IIEALI'11 <br /> DEPA10-NIENT <br /> Terracon prepared a Soil Suitability Study and Nitrate Loading Study (SSNLS) for the site dated <br /> December 13, 2019, Terracon Project No. NA197095. Based on Terracon's SSNLS report, the <br /> site is proposed to be developed with a 1,900 square foot, 3 bedroom, 2 bathroom residence and <br /> average daily flow for the septic system of 420 gallons per day (gpd). The nitrate levels for the <br /> proposed residence was estimated at 24.2 milligrams per liter nitrate as N (mg/L-N), above the <br /> EPAs maximum contaminant level (MCL) of 10.0 mg/L-N. This letter is in response to the Soil <br /> Suitability/Nitrate Loading Study letter dated January 14, 2019, SR0081528 prepared by the San <br /> Joaquin County Environmental Health Department (EHD) for the subject site. The EHD <br /> recommended engineered nitrate reduction design for the septic system and recommended the <br /> on-site groundwater well be tested for Nitrate as N and 1,2-dibromo-3-chloropropane (DBCP). <br /> In February 2020, the EHD approved a revised calculation method for long term average <br /> discharge of waste water and recommended 100 gallons for the first bedroom and 50 gallons for <br /> each additional bedroom. The EHD additionally approved an adjustment to the evapotranspiration <br /> (ET) rate based on net rainfall recharge calculation utilizing University of California (UC) plant <br /> factors (PF)for established landscape plants. <br /> Based on the approved EHD methods, Terracon revised the long term average daily flow from <br /> 420 gpd to 200 gpd for the proposed three bedroom residence. Terracon adjusted the estimate <br /> of net rainfall recharge from 2.89 inches per year to 5.84 inches per year based on current land <br /> conditions of the site which consisted primarily of a few trees and vacant land with unirrigated <br /> seasonal grasses. It should be noted there were no PF's available for seasonal <br /> grasses/vegetation; therefore, Terracon assigned a plant factor of 0.45 which is between desert <br /> adapted plants (PF 0.3) and general turfgrass (PF 0.6). <br /> Terracon Consultants Inc. 902 Industrial Way Lodi, CA 95240-3106 <br /> P 209-367-3701 F 209-333-8303 terracon.com <br /> i <br />