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f Soil Suitability/Nitrate Loading Study Proposed Global Carrier Inc. ■ Manteca, California 1rerracon August 8, 2018 ■ Terracon Project No. NA187034 1.6.2 Number of Percolation Tests One shallow boring (131) percolation test was conducted. 1.6.3 Boring Preparation and Presaturation The soil boring (61) was excavated to a depth of 3.5 feet bgs on July 25, 2018. Approximately six inches of"pea gravel"was placed in the bottom of the open boring. A 2.0-inch diameter PVC pipe with perforations towards the bottom was installed on top of the gravel and the annular space was backfilled with "pea gravel". Presaturation of the percolation test hole occurred on July 25, 2018 in anticipation of the percolation test the following day; however, due to time limitations, the test was not able to be performed therefore the boring was presaturated again on July 26, 2018. Boring B1 was additionally presaturated on July 31, 2018 in preparation for a second percolation test. Presaturation consisted of a water column approximately 1 foot over gravel. 1.6.4 Condition of Borings after Presaturation July 26, 2018, after the initial 24-hour presaturation period, boring B1 was found to be dry and intact. On July 27, 2018, water was found at the bottom of boring B1 likely due to the previous day presaturation. On July 31, 2018 boring B1 was dry and intact. On August 1, 2018 boring B1 was found to be dry and intact on the day of testing. 1.6.5 Percolation Test Procedure A percolation test was conducted on July 27, 2018 and had a duration of four hours with readings taken every 30 minutes. The final 30 minutes of the test was observed by EHD representative Mr. Jeffrey Wong; however, the percolation test had an unsatisfactory percolation rate likely due to the absence of head space at the end of the test. Terracon spoke with Mr. Stephen Shih of the EHD who suggested allowing the boring to dry out over the weekend and re-running the test the following week. A second percolation test was conducted on August 1, 2018 in accordance with the requirements of the San Joaquin County EHD. Approximately 0.5 feet of water was added over gravel and the drop in water level was recorded every 30 minutes over a four hour period. The final 30 minutes of the test was observed by EHD representative Ms. Betty Ho who signed the percolation test form. Measurement of the water level during the percolation test was from a fixed reference point on the PVC casing using a calibrated Solinst electric water level detector with a depth accuracy of 0.01 feet. All tabulated values on the field data sheet are in decimal feet. A copy of the field data signed by the County Inspector is included in Appendix F. Responsive■ Resourceful ■ Reliable 11