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September 20, 2021 <br />SOIL SUITABILITY STUDY / NITRATE LOADING STUDY <br />33503 S KOSTER ROAD <br />TRACY, CALIFORNIA <br />1.0 INTRODUCTION <br />Petralogix Engineering, Inc. has been retained by Ms. Pedro Perez to conduct a Nitrate <br />Loading Study (NLS) and Soil Suitability Study (SSS) for the property located at 33503 S <br />Koster Road, Tracy, San Joaquin County, California. The site assessor parcel number (APN) <br />is 255-90-32. Proposed development consists of a two-bedroom, two-bath residential <br />accessory dwelling unit (ADU). The parcel currently has one primary single-family residence <br />with three bedrooms and two baths. The Environmental Health Department has requested <br />the owner to submit a Soil Suitability Study (SSS) and Nitrate Loading Study (NLS) to assess <br />soil conditions pertaining to the development of the parcel and associated planned septic <br />system as well an evaluation of the projects potential to contaminate surface and <br />groundwater with nitrate. <br />The purpose of the SSS is to determine whether the soils are suitable for use with a septic <br />system. The study was conducted in accordance with the requirements of Section 9- <br />1105.2(d) of the San Joaquin County Development Code. An important element of an SSS <br />consists of conducting percolation tests to determine if soils meet the required absorption <br />rates, as required by the San Joaquin County, Public Health Services, and Environmental <br />Health Department (EHD). This report has been formatted to correspond with the Soil <br />Suitability Study Requirements Checklist of the San Joaquin County Environmental Health <br />Department (EHD) dated July 14, 2003. <br />The San Joaquin County Environmental Health Department recognizes nitrate <br />contamination as a significant threat to the surface and groundwaters of the County. <br />Groundwater quality may be impacted by nitrate contamination where percolating effluent <br />leaches into the ground, should this effluent reach groundwater. Due to the EHD concerns <br />regarding nitrate leaching into the surface and groundwaters from septic systems, a nitrate <br />loading study is required by the EHD for the proposed development to measure the potential <br />concentration of percolating effluent and rain fall over a long period of time. This report has <br />been prepared to meet the requirements of the San Joaquin County EHD’s Nitrate Loading <br />Study Requirements Checklist, dated July 14, 2003. <br />A simple mass balance formula, as discussed in the article by Hantzshe and Finnemore1 in <br />Ground Water, provides a method for nitrate loading analysis to estimate long-term <br />groundwater nitrate impacts for a wide area. Based on the Hantzshe and Finnemore study, <br />water quality in the upper saturated groundwater zone approximates the quality of <br />percolating recharge waters, which the authors believe is a reliable planning tool to estimate <br />1 Hantzshe N., Finnemore, E.J., 1992. Predicating Ground-Water Nitrate-Nitrogen Impacts. Ground Water, Vol 30, No 4.