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Mr.George Rose December-19;2001 Page 2 Percolation Tests A percolation test was performed to demonstrate the capacity for soil percolation for use with an on site septic system.A shallow percolation test is 'required to be set to a depth of 3- eet by the County. Based on previous work on the site,these shallow zones will often not satisfy the minimum percolation rate of<60 minutes per inch, thcrefore-an alternate deeppercolation test-is set adjacent to the shallow test. The depth of the deep percolation test was determined by settiri t sin.adjacent-to4he£irst:sufficiently permeable material encountered'(usually a clean- ffisandy soil)'fo and between the depth of 4-feet to 15- e e•au er hole is 6-inches in diameter. The casing used for the test was a 2-inch diameter,PVC pipe •w.th an open end on the top and bottom.Perforations were placed on the bottom 1-foot.of the.pipe. 'Two(2) in es of"pea gravel'was placed in the bottom of the hole, the casing was installed; and 1-foot of "pea grave ''vias backfilled in the annular space. One (1)houi and four(4)percolation tes s r 0 e 8,an 'December 5=6,2001 in accordance with the requirements of SJC PHS-EHD. in a location -that be use "for a.future septic sy4m. All the percolation tests were observed'by Lisa Me ena o ' SJC PHS-EHD. An ele c was used to measure the- water.drop over an minimum interval of 10 minutes during the tests.The units of the sounder are in feet with a 1/100-foot resolution. Presently;the sounder is referenced to 40-feet as-0-feet. For example,44.5-feet on the sounder tape is actually 4.5-feet:in distance. To convert decimal feet to inches,multiply decimal feet by twelve(12).'A satisfactory percolation rate was achieved on all the parcels. Table.l presents a summary of the shallow,and deep percolation test inforn-ation for the twelve(12).parcels. The field percolation test sheets are,attached in the appendix. . c -Table 1. Summary of the percolation tests. Parcel,Perc.Test - Size Percolation Depth of Date of Soil Type'." Name Rate. Test, Test at Test Depth Parcel 21,shallow, 2.13 acres 31.3 min/in 3.0 ft 1215/01 Brown sandy silt. Parcel 2'1,deep 2.13 acmes 4.17 min/in 15.0 ft 11/2I/01 Brown sand with silt. Parcel 22,'shallow 2.10 acres:. 25 min/in 3"0 ft 12/5/01 .'Brown sandy silt with clay.. Parcel 22,deep '2110 acres X1.67 min/in 15.0 ft 11/21/01 Brown sand withsilt. " Parcel 23,shallow 2.10 acres 5 min/in 3.0 ft 12/5/01 Brown sandy silt with clay- Parcel 23,deep 2.10 acres'. .1.51 min7in 9.0 ft 11/21/01. Brown sand with silt Parcel 24,shallow' .2"10 acres Fail " 3.0 ft 1215101 Brown sandy silt.with clay.' Parcel 24,deep 2.10 acres 1.51 min/in 9.0 ft 11/2IYOI Brown sand with silt. Parcel 25,shallow 2.10 acres 15.6 min/in 3.0 ft 12/,S/OI Brawn sandy silt with clay.