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Mr. George Rose December 19,2001 age 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, therefore an alternate deep percolation test"is set adjacent to the shallow test. The depth of the deep percolation test was determined by settm tca c�sng-adj went-toxheXust.suff ciently permeable material encountered(usually a cleat` sandy soil) found between the depth of 4-feet to 15- e frau- er hole is 6-incbes in diameter. The casing used for the test was a 2-inch diameter,PVC pipe w th an o/pen 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 'was backfilled in the annular'space. One (1)hour and four(4)percolation tes s ere c e . , 8,an December 5-6,20011 n accordance with the requirements•of SJC PHS-EHD. _ in a location that.rm1d be uses 'fort/a future-septic sysjfm. 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 1/140-foot resolution. Presently;elle sounder is referenced to 40-fee -feet For example,44.5-feet on the sounder tape is actually 4.5-feet.in distance. To convert decimal feet to in multiply decimal feet by twelve(12). "A satisfactory percolation rate was achieved on all the parcels. Table I presents a summary of the shallow and deep percolation test information for the twelve(12)parcels. The field percolation test sheets are attached in the appendix. . 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 minlin 3.0 ft 12/5101 ` Brown sandy silt. " Parcel 21,deep 2.13 acres 4.17 min/in 15.0 ft 11/21/01 -Brown sand with silt. Parcel 22,shallow 2.10 acres 25 minlin 3.0 ft 1215101 Brown sandy silt with clay.. Parce122,deep 2:10 acres <1.67 min/in 15-0 ft 11/21/01 Brown sand with silt. Parcel 23;shallow 2.10 acres .5 min/in 3.0 ft I2/5101 Brown sandy silt with clay:" Parcel 23,deep 2.10 acres 1.51 min/in .9.0 ft 11121101 Brown sandwith.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 1'1121701 Brown sand with silt., �r Parcel 25,shallow 2.10 acres 15.6 min/in 3.0 ft 121",5101 Brown sandy silt with clay. z � a r ,