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March 17, 2021 SOIL SUITABILITY STUDY / NITRATE LOADING STUDY 11655 S UNION ROAD MANTECA, CALIFORNIA 1.0 INTRODUCTION Petralogix Engineering, Inc. has been retained by Mr. Moises Chavez to conduct a Nitrate Loading Study (NLS) and Soil Suitability Study (SSS) for the property located at 11655 S Union Road, Manteca, San Joaquin County, California. The site assessor parcel number (APN) is 204-030-07. Proposed development consists of one 1,493 square-foot, two-bedroom, one-bath residential accessory dwelling unit (ADU). The parcel currently has one primary single family 1,723 square-foot residence with three bedrooms and one bathroom. The Environmental Health Department has requested the owner to submit a Soil Suitability Study (SSS) and Nitrate Loading Study (NLS) to assess soil conditions pertaining to the development of the parcel and associated planned septic system as well an evaluation of the projects potential to contaminate surface and groundwater with nitrate. The purpose of the SSS is to determine whether the soils are suitable for use with a septic system. The study was conducted in accordance with the requirements of Section 9-1105.2(d) of the San Joaquin County Development Code. An important element of an SSS consists of conducting percolation tests to determine if soils meet the required absorption rates, as required by the San Joaquin County, Public Health Services, and Environmental Health Department (EHD). This report has been formatted to correspond with the Soil Suitability Study Requirements Checklist of the San Joaquin County Environmental Health Department (EHD) dated July 14, 2003. The San Joaquin County Environmental Health Department recognizes nitrate contamination as a significant threat to the surface and groundwaters of the County. Groundwater quality may be impacted by nitrate contamination where percolating effluent leaches into the ground, should this effluent reach groundwater. Due to the EHD concerns regarding nitrate leaching into the surface and groundwaters from septic systems, a nitrate loading study is required by the EHD for the proposed development to measure the potential concentration of percolating effluent and rain fall over a long period of time. This report has been prepared to meet the requirements of the San Joaquin County EHD's Nitrate Loading Study Requirements Checklist, dated July 14, 2003. A simple mass balance formula, as discussed in the article by Hantzshe and Finnemorel in Ground Water, provides a method for nitrate loading analysis to estimate long-term groundwater nitrate impacts for a wide area. Based on the Hantzshe and Finnemore study, water quality in the upper saturated groundwater zone approximates the quality of percolating recharge waters, which the authors believe is a reliable planning tool to estimate the potential impact to groundwater, as well as a useful source of analysis to official planning agencies. The equation utilized by the Hantzshe and Finnemore approach considers the development area, soil denitrification factor, rainfall volume, rainfall nitrate concentrations, waste effluent quantity, and waste effluent nitrate concentration. The formulas, calculations, and assumptions are provided on Plates 8 and 9. The units of nitrate used in the mass balance equation are nitrate-N, whose maximum drinking water contaminant level is 10 mg/L. I Hantzshe N., Finnemore, E.J., 1992. Predicating Ground-Water Nitrate-Nitrogen Impacts. Ground Water, Vol 30, No 4. Petralogix Engineering, Inc. i 26675 Bruella Road, Galt, Ca 95632 (209)-400-5729 Twww.petralogixcom