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Soil Suitability / Nitrate Loading Study Irerracon <br /> Thor Property a Stockton, CA <br /> July 19, 2018 a Terracon Project No. NA187029 <br /> 1.5.4 Discussion of Soil Lithology <br /> A visual inspection of the shallow and deep soils from the test borings points to unfavorable <br /> conditions for shallow septic disposal areas due to the slow permeability of the clay soils. <br /> Generally speaking, coarse-grained soil has a greater potential for percolation than fine-grained <br /> or cemented soil. The area is known to have clay strata with depth as well as "hardpan" or <br /> cemented soils which have low porosity. For this reason, seepage pits are used with leach lines <br /> in various areas of the county. <br /> 1.6 Percolation Test Information <br /> 1.6.1 Percolation Test Locations <br /> Refer to Section 1.5.1 and Appendix A, Exhibit 2. <br /> 1.6.2 Number of Percolation Tests <br /> Two percolation tests were performed on the site including one shallow percolation test(P1 at 3.5 <br /> feet bgs) and one deep percolation test (P2 at 25.0 feet bgs). <br /> 1.6.3 Boring Preparation and Presaturation <br /> The shallow soil boring (P1) was excavated on June 5, 2018. Approximately two inches of "pea <br /> gravel" was placed in the bottom of the open boring. A 2.0-inch diameter PVC pipe with <br /> perforations towards the bottom was installed on top of the gravel and the annular space was <br /> backfilled with "pea gravel'. Presaturation of the percolation test hole occurred approximately 24 <br /> hours prior to the day of testing. The depth of water used to pre-soak was approximately 1.0 foot <br /> above the bottom of the boring. <br /> The deep soil boring (P2) was excavated on June 29, 2018. Approximately two inches of "pea <br /> gravel" was placed in the bottom of the open boring. A 2.0-inch diameter PVC pipe with <br /> perforations towards the bottom was installed on top of the gravel and the annular space was <br /> backfilled with "pea gravel'. Presaturation of the percolation test hole occurred approximately 24 <br /> hours prior to the day of testing. The depth of water used to pre-soak was approximately 2.0 feet <br /> above the bottom of the boring. <br /> 1.6.4 Condition of Borings after Presaturation <br /> After the 24-hour soak period, boring P1 was found to be intact with approximately 0.2 feet of <br /> water in the boring on the day of testing. <br /> Responsive ■ Resourceful ■ Reliable 9 <br />