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Soil Suitability and Nitrate Loading Evaluation CTE Job#25-0710 Great Pacific Nut—Nut Processing Facility Expansion 3501 Lehman Road Tracy, California August 1 2019 Pae 6 of 10 saturation period a 2-inch column of water had'"dissipated" from P-IX and all 12-inches had dissipated from P-1. Percolation testing was then performed immediately in P-1 by adding water to a level of 6± inches above the top of the 2 inches of gravel placed at the base of the test hole. The test was performed in P-1X by adjusting the water level to 6-inches above the gravel. Recordings were made of the change (drop) in water level at regular time intervals and water level was refilled after each interval. Specific details are included on the attached percolation test data sheets located in Appendix-A. 7.2 Percolation and Infiltration Rates The soil percolation rate is defined by the average time in minutes for a 1-inch column of water to "seep" into the soil. Percolation rate was calculated in minutes per inch (MPI) by dividing the time (in minutes) by the change (drop) in water level (in inches). No correction factor was used in the calculation for the 6-inch boring diameter. Percolation test "P-1X" achieved a steady percolation rate of 480 minutes/inch at 36-inches bgs and "P-1" achieved a steady percolation rate of 16.0 minutes/inch at 38-inches bgs. In general, the percolation rates are not considered inconsistent with those typical of the soil types encountered at the site/vicinity. 8.0 NITRATE LOADING CALCULATIONS Per SJEHD requirements, the following summarizes our nitrate loading calculations for the proposed leach field. The state drinking water standard for nitrate is 45 milligrams per liter (NO3) and 10 mg/1 as Nitrogen (N) in groundwater. Presented below is our evaluation of nitrate loading which uses the Hantzshe mass balance equation (source: Predicting Groundwater Nitrate-Nitrogen Impacts, Hantzsche and Finnemore; 1992) attached as Appendix C. Ne = Calculation of nitrate-nitrogen in groundwater resulting from leach field source and precipitation (mg/l, as N). L,€f :T.