SU0004298 - Laserfiche WebLink

Home Browse Search

The cemented, fine sandy silts hardpan continues down to 8 feet. It was decided to test the permeability of the hardpan at this depth. After drilling the 8 feet boring with solid stem auger, the hole was cleaned out with ahand-auger. The cementation of the soils at this depth was clearly evident during the hand-drilling. Percolation testing of this boring is discussed below. ENCOUNTERED SOIL MORPHOLOGY FROM DOMESTIC WELL DRILLING The following soil descriptions were encountered during the drilling of the Russell's domestic well. Although the well was drilled to more than 300 feet, soil descriptions are provided to 130 feet where the groundwater was encountered. 0-3 Top Soil 3-24 Clay 24-27 Sand 27-39 Clay 3945 Sand and Gravel 45-50 Clay 50-64 Sand 64-130 Clay-Groundwater Encountered at 130 ft 130-134 Black Sand PERCOLATION TESTING Three perc test borings were drilled using the B-24 drill rig and solid stem auger. The first boring was drilled to a depth of 22 feet. This boring gave an illustration of both the shallow and deep soil morphology. A well graded silty sand was encountered at 22 feet, consequently, the boring was terminated at this depth instead of drilling to a maximum of 25 feet. The second boring was drilled to a depth of 42 inches, representative of effluent percolation from leachlines. A third boring was drilled to a depth of 8 feet, as referenced above. This boring was unofficially perc tested to determine the permeability characteristics of the encountered hardpan. The percolation test boring locations are illustrated on the Site Plan found in Appendix A. After drilling the shallow perc test boring, the sidewalls were scored with a pry-bar and the loose material removed. The 8 foot and 22 foot test borings could not be scored due to its depth. Two inches of pea gravel was placed at the bottom of each boring to prevent scour and three-inch perforated PVC pipe was inserted in all three test borings. The perc test borings were pre-saturated on October 20, 2005 at 1500 hrs with 12 inches of clear water in accordance with EHD regulations. On October 21, 2005, 0800 hrs,percolation testing commenced for all three borings. Post-soak status for each test boring is illustrated in the Table below. Since standing water was measured in the shallow test boring,EHD Perc Test Procedure 91 was conducted for this boring. No water remained in the deep test boring, therefore, EHD Test Procedure#2 was conducted. The last half hour of the tests was witnessed by Mike Escotto, R.E.H.S. of the San Joaquin County Environmental Health Department. The following Table summarizes the proposed Parcel number, septic system structure to be installed based on depth of acceptable perc rates, Street Address, A.P.N. Number,post soak period status and percolation test results at the perc test depth: Page-2- Chesney Consulting