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Y t Soil Suitability and Nitrate Loading Evaluation-Update-2 Page 11 of 18 Great Pacific Nut—Nut Processing Facility Expansion 3501 Lehman Road,Tracy, California September 6, 2019 CTE Job#25-071 OG 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. Owing to variations in material type and depth, percolation rates would typically be expected to fluctuate somewhat across a site and are also dependent upon actual construction, depth, size, location and workmanship of the drainage element. Based on percolation test results, as described above, the soil conditions at the site are considered suitable for a storm water disposal system in the vicinity of P-2 and P-3 at 10.0 ft bgs. In the vicinity of P-1X (where the original proposed leach field was located) the percolation rate was determined to be 480 MPI which is slower than the maximum rate allowed of 60 MPI in San Joaquin County. In the vicinity of P-1 (where the new proposed leach field is located) the percolation rate was determined to be 16 MPI less than 60 MPI and considered to meet criteria for a standardized design.. The percolation test measures the length of time required for a quantity of water to infiltrate into the soil and is commonly referred to as the "percolation rate". It should be noted that the percolation rate is related to, but not equal to,the infiltration rate. While an infiltration rate is a measure of the speed at which water progresses downward into the soil, the percolation rate measures not only the downward progression but the lateral progression through the soil as well. This reflects the fact that the surface area for infiltration testing would include only the horizontal surface while the percolation test includes both the bottom surface area and the sidewalls of the test hole. The calculated conversion from percolation rate to infiltration rate is located within Appendix A. Based on the test results and conversions, the resulting percolation rates in min/inch and infiltration rates in gal/sf/day are listed in Table 2.3 below. The observed infiltration rates listed below do not include a safety factor. It is commonly accepted SACRAMENTO - FREMONT - MODESTO INSPECTION&TESTING-GEOTECHNICAL-ENVIRONMENTAL-CONSTRUCTION ENGINEERING