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Soil Suitability Study Irerracon Flag City#4 Lodi, California February 14, 2019 Terracon Project No. NA187043 5.4 Discussion of Soil Lithology A visual inspection of the shallow and deep soils from the test borings points to favorable conditions for shallow septic disposal systems; however, the area is known to have "hardpan" or cemented soils which have low porosity. For this reason, sumps and/or seepage pits are often used with leach lines in various areas of the county. Generally speaking, coarse-grained soil has a greater potential for percolation than fine-grained or cemented soil. 6.0 PERCOLATION TEST INFORMATION 6.1 Percolation Test Locations A percolation test was conducted on the northern portion of the site. Refer to Section 5.1 and Appendix A, Exhibit 2 for the approximate percolation test location. 6.2 Number of Percolation Tests One percolation test was performed on the site at boring B1 at 3.5 feet bgs. 6.3 Boring Preparation and Presaturation The shallow soil boring (B1) was excavated on January 28, 2019. Approximately two 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 approximately 24 hours prior to the day of testing. The depth of water used to pre-soak the boring was approximately 1.0 foot above the top of the gravel. 6.4 Condition of Borings after Presaturation Boring B1 was found to be dry and intact after the 24-hour pre-soak period. 6.5 Percolation Test Procedure The percolation test was conducted in accordance with the requirements of the San Joaquin County EHD. The shallow percolation test (B1 at 3.5 feet bgs) was conducted on January 29, 2019. As there was no water remaining in the test hole overnight, Terracon conducted the percolation test by following Procedure #2. Terracon added clear water approximately 0.5 feet above the top of the gravel and recorded the drop in water level at thirty minute intervals for a four hour period. Measurement of the water level during the percolation tests 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. The percolation test was observed by Mr. Naseem Ahmed, EHD representative. Responsive ■ Resourceful ■ Reliable 10