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October 23, 2009 Page 5 of 9 Our Project Number: LGS0090519 Table 2. Soil Boring L Depth Interval (ft) Soil Type Unified Soil Classification 0-3.5 Medium brown, sandy silt SM A visual inspection of the soils from on-site drilling indicates potential for percolation because of the nature of the soils. A percolation test is the best method to determine the suitability of the soils for a septic disposal area. Please see the next section for percolation test results. Generally speaking, coarser-grained soils have much greater potential for percolation than fine- grained or cemented soils. 5.0 PERCOLATION TEST INFORMATION A site map indicating the locations of the percolation test holes is included as Plate 1 in !(f• !) Appendix A of this report. One shallow percolation test was conducted on each of the 21 proposed parcels. The soil borings were advanced on the property with a hand auger. A 1.5- inch diameter PVC pipe with perforations on the bottom was used to measure the drop of water in the percolation test boring. Approximately two (2) inches of "pea gravel' was placed in the bottom of the open soil boring and then the PVC pipe was installed on top of the gravel. "Pea gravel" was then used to backfill in the annular space. Presaturation of the percolation test holes occurred approximately 24 hours prior to the day of testing. The depth of water used to pre-soak was 12 inches above the bottom of the boring. After the 24-hour soak period, the presaturated holes were found to be intact and dry on the day of testing. If; 5.1 Percolation Test Procedure Percolation tests were conducted for the borings on August 18, 20, 26, and 27 of 2009 in accordance with the requirements of the EHD. A four (4) hour percolation test was performed for the test. The last half an hour of the test was observed by either Michael Escotto or Lisa Medina (depending on date), both Senior Registered Environmental Health Specialists, at EHD. Measurement of the water level during the percolation test was from a fixed reference point on the PVC casing using an electric well sounder with a depth accuracy of 1/100th foot. All tabulated values on the field data sheet are in decimal feet. After water drop was observed, the holes were checked for refill. The refill level was approximately 0.5 ft (6 inches) of water above the bottom level of the percolation test hole. The readings were taken every 30 minutes for a period of four (4) hours. 5.2 Percolation Test Forms and Results The completed percolation test form is included in the Appendix B of this report. A shallow percolation test is defined by the EHD as being between 36 and 42 inches in depth; a satisfactory percolation rate for a shallow test is less than or equal to 60 minutes per inch drop. A deep percolation test is defined as being between 3.5 and 25 feet in depth; a satisfactory 902 Industrial Way•Lodi,CA 95240-209.367.3701 •Fax 209.369.4228 02009 Neil O.Anderson&Associates,Inc