SU0004298 SSNL - Laserfiche WebLink

Home Browse Search

May 25, 2004 ` NOA Project Number: E04061A Page 9 5.3 Soil Lithology Observed and Septic Applicability ` The soil encountered in the borings was similar to that reported in the San Joaquin County Soil Survey soil for the area(USDA, 1992). Representative soil logs prepared by NATS are presented in the appendix of this report. According to these logs,the typical soils encountered were brown silty sand to approximately two feet, followed by brown silt and sandy silt to approximately ten feet, followed by silt, sand, and sandy silt down to 25 feet. Silt and sand typically exhibit acceptable percolation properties. 6.0 PERCOLATION TEST INFORMATION 6.1 Percolation Test Boring Locations One to four percolation tests were conducted on each proposed lot. At least one satisfactory 6. percolation test per lot was evaluated by EHD. Please refer to the scaled site plan for the exact locations (Plate 1) or appendix detail drawings attached to the percolation test forms. [Ap rcolation test was not performed on lot 46,the location of the exisring structures and septicm. Should a second dwelling unit be desired on lot 46, a percolation test in the proposedc disposal field may be required by the EHD. 6.2 Boring Preparation and Specifications L. To complete the percolation tests, 55 soil borings were advanced on the Site by staff of NATS. The borings were advanced between the dates of Apri120 and May 19, 2004 using a track- mounted drill rig. The depths of the borings ranged from 3.3 to 20.8 feet, and are listed in Table 5,below (personal communication, David Kaestner,May 25, 2004). A 2-inch diameter PVC pipe with perforations on the bottom was used to measure the drop of water in the percolation test boring. Approximately 2 inches of"pea gravel" were placed in the bottom of the open soil boring, then the PVC pipe was installed on top of the gravel. Several feet .. of"pea gravel'were backfilled in the annular space (personal communication, David Kaestner, May 25, 2004). 6.3 Presaturation of Borings Presaturation of the percolation test holes occurred 24 hours before each percolation test. The depth of water used to pre-soak was 12 inches above the bottom of the borings. After the 24-hour soak period, most of the presaturated holes were found to be intact and dry before the start of the percolation test. A few of the shallow percolation test holes were found to be wet after the 24-hour soak period; these holes failed the subsequent percolation test (personal r