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r� rFl.-I NTRODUCTION Mr. Roger Towers of House and Land, Inc. owns three adjoining parcels consisting of 18.96 total acres in a rural, unsewered portion of San Joaquin County. He is proposing to construct a maximum of two, single family residential (SFRs) units on each of the three parcels, for a total of six SFR units. The second SFR on each of the three parcels is to be considered the "second unit dwelling." This report presents the test results and research findings of the Nitrate Loading and Soil Suitability Studies conducted as a prerequisite for this proposed development. A Tentative Map has been produced by the surveying firm of Aspen Survey of Modesto. The San Joaquin County Environmental Health Department (PHS-EHD) requires Soil Suitability Studies and Nitrate Loading for projects in unsewered areas, or for projects which may potentially impact the underlying groundwater with nitrate. This report complies with the San Joaquin County Development Title, Section 9-1105.2 for a Nitrate Loading Study and Soil Suitability Study. Additionally, this proposed project must comply with the Environmental Health Department Sewage Standards, specifically Section 10: "Requirements for Waste Disposal for New Land Developments." The primary concern of nitrate in drinking water is that high concentrations can cause methemoglobinemia in infants and induce abortion or death in cattle. This disease in humans occurs through a series of complex chemical reactions within the hemoglobin in the blood. Only infants and young children are susceptible, which is extremely rare. Nitrate concentrations in water can be expressed in two different terms: 1.) As the weight of the nitrate molecule, which is one atom of nitrogen and three atoms of oxygen for an atomic weight of 62 units. Or, 2.)Nitrate can be expressed as the amount of the nitrogen atom itself. This one atom of nitrogen(N) in a nitrate molecule contributes 14 atomic weight units to the weight of the nitrate molecule. The ratio of weight of the nitrate molecule (NO3) to the atom (N) is 62114 or approximately 4.5. The U.&E.P.A. has established the Maximum Contaminant Level (MCL) of nitrate in drinking water at 45 mg/l as nitrate. Due to the ratio described above, the MCL is sometimes reported as 10 mg/l as nitrate-nitrogen. The subject property is located 1.5 miles south of Highway 132 and 1.25 miles east if Interstate 5, near the Vernalis area. No municipal water and sewer serve the area and probably never will. The property is located in a portion of Section 5, Township 4 South, Range 6 East M.D.B. &M. It is bound to the north by open land. To the south is a single family residential structure on approximately five acres of land. To the east are the Delta-Mendota Canal and an apricot orchard. To the west are Koster Road and the Granite Company gravel quarry. Staff from the Environmental Health Department has stipulated these studies address the following items: ✓ Investigate the physical and chemical surface and subsurface soil characteristics of the subject property and conduct percolation testing on each of the designated parcels for septic system design parameters. Assess the agricultural capabilities and characteristics of the on-site soils. 1 Chesney Consulting