SR0083847_SSNL - Laserfiche WebLink

Home Browse Search

Soil Suitability Report BSK Job E21-002-01B Cascade BESS Project August 26, 2021 Stockton, California P a g e | 7 6.PERCOLATION TEST INFORMATION Percolation testing was performed at three locations named PT-1 through PT-3 (Shown in Figure 1-C) at a depth of approximately 4 feet. A BSK engineer performed the test under the supervision of a San Joaquin County Environmental Health inspector following the San Joaquin County Environmental Health Department test procedure. 6.1 Percolation Test Hole Preparation Description The percolation tests were prepared on February 1, 2021 and tested on February 2, 2021 following the 24-hour soak time. The holes were drilled down to a depth of 4 feet below ground surface with hand auger equipment, and the hole diameter was approximately 4 inches. After the sides were scrapped and loose material was removed from the hole, 2-inches of fine gravel was added to the bottom of the hole. Then, the hole was presoaked 24-hours before testing by adding a minimum of 12 inches of water above the gravel layer. 6.2 Percolation Test Hole Post-Soak Description On February 2, 2021, the holes still had water, but the holes were intact and in good condition. 6.3 Percolation Test Description The work was performed in accordance with the San Joaquin County EHD Policy #98-02. On February 2, 2021, the holes were still filled with water. Some of the excess water was removed before adding fresh clear water to approximately 6 inches over the gravel layer. From a fixed reference point at the top of the well screen, the water level was measured with a measuring stick in 30-minute intervals for a total of 4 hours per test location. The percolation rate was calculated based on the field data. The Complete Percolation Test Form with readings were signed by the EHD inspector and are shown in Appendix E. 6.4 Potential Predicted Problems Based on percolation testing conducted on site, CPC Soil Types range from Type 2 to Type 5 are considered to be in the acceptable range for design purposes. 6.5 Percolation Testing Results The calculated percolation rates are summarized in a table below, and the reports are provided in Appendix E. The use of the septic systems should follow the San Joaquin County On-site Wastewater Disposal Standards. Table 1: Summary of Percolation Testing Location Soil Classification Percolation Rate (minutes/inch) PT-1 @ 4’ bgs CL 10 PT-2 @ 4’ bgs CL 25 PT-3 @ 4’ bgs SC 2