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15999 W CORRAL HOLLOW RD Project No.2019-00027 P a g e 110 Generally speaking, coarser-grained soils have much greater potential for percolation than fine- grained or cemented soils. 6.0 PERCOLATION TEST INFORMATION A site map indicating the location of the percolation test hole location is included as Plate 2 in Appendix A of this report At the proposed septic leach field for the project(Site 300- Proposed Building T8021) one shallow percolation test was conducted. The test hole location's latitude and longitude was taken using a submeter accurate(2.5 cm)Trimble GeoHX GPS unit,which was differentially corrected.The latitude and longitude are 37.667148 and -121.537373 degrees, respectively. The shallow soil boring was advanced on the property with a hand auger on June 17, 2019. A 2.0-inch diameter PVC pipe with perforations on the bottom was used to measure —e—rd op o�water in the percolation test boring. Approximately two (2) inches of"pea gravel"was placed in the bottom of the 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 the shallow test holes was 12 inches above the bottom of each shallow boring. After the 24-hour soak period,the presaturated hole was found to be intact and dry on the day of testing. The final percolation rates were determined based on the EHD Percolation Test Procedure form 42-01-002, revised 4-14-2018, based on if water or no water remains in the test hole overnight. The onsite testing was supervised by Sukhreeton Kaur(of the SJC EHD)on June 19,2019. 6.1 Percolation Test Procedure Percolation testing was conducted for the onsite boring on July 19, 2019 in accordance with the requirements of the EHD. A one-hour percolation test was performed for the onsite test. The last two ten-minute readings of the test were observed by Sukhreeton Kaur, Environmental Health / Specialist,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 10 minutes for a period or one(1)hour. 6.2 Percolation Test Forms and Results The completed percolation test permits and test forms are included in the Appendix C 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 percolation rate for a deep test is 30 min/in or less. One percolation test must demonstrate a satisfactory percolation rate within the proposed septic system disposal field of a site (or parcel)to utilize a standard septic system. Details of the percolation tests are summarized in the table below. Petralogix Engineering,Inc. 26675 Bruella Road,Gaft,Ca 95632 (209)-000-5729 www.petralogix.com