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II. SOIL SUITABILITY STUDY A. Surrounding Septic System Information A review of Application Permits on file with the Environmental Health Department reveals there has been one Application for Repairs/Additions to septic systems on Mossdale Road exclusively, located at 640 Mossdale Road. This can be considered a very low number of Repairs/Additions/ Replacements, however, considering the low septic system density, this is plausible. Soil testing was conducted on samples retrieved from a single, exploratory boring. The boring was drilled near the center of the primary disposal area, as denoted on the Percolation Test Form. Physical and analytical chemistry testing were conducted on the samples obtained, discussed below. B. Soil Physical Test Results: Standard Penetration Tests, Particle Size Analysis and Percolation Testing Soil physical testing began during the drilling procedures by using the Standard Penetration Test (SPT). It is known that the referenced embankment was constructed by the Brown Sand ComnanY with spoils of undesirable soil material, pnmarily cls and silt. The attached Logs of Borings for both holes illustrate the number of blows needed to advance the split spoon sampler, one foot (ATM D-1586). SPT rests for the Exploratory Boring in the area of the proposed filter bed indicate stiff clay soil at 5 feet. At 10 feet, the soil is veryJiud. The silt soil at 15 feet is medium dense, and the silt soil at 20 feet, which can be considered the capillary fringe is a loose, or soft soil. Soil samples were retrieved during the SPT test from the five, 10, 15, and 20 foot depths. Particle Size Analysis was done on the three samples by A&L Laboratories of Modesto under the attached Chain of Custody. Laboratory USDA classifications reveal_the underlying soil to consist of a clay loam. loam and siltoalsLsoils. In addition to USDA classifications,the Unified Soil Classification System describes the coil samples (alsq denojed on the Feld Percolation Test Form) as silty, lean clay, and a silt. These soil classifications are summarized in the Table 1, Page 4. The second physical tests to be conducted were percolation tests in the location of the primary filter bed, as described: On December 15, 2004, one perc test boring of 38 inches and one deeper test boring at 82 inches (7 feet) were drilled with a B-24 Mobile Drill Rig. The sidewalls of the borings were scored with a pry-bar and the loose material removed with a hand auger. Two inches of fine gravel was placed at the bottom and three-inch perforated PVC pipe was inserted into each hole. Both test borings were pre-saturated with water, approximately 24 hours before the start of testing. On Decembe j , 2004,percolation testing commenced for the two borings. There was approximatelnches of standing pre-soak water in both borings. Each boring was refilled to approximately six inches of head water and the percolation tests were conducted over a four-hour period to induce maximum soil saturation. Test results reveal a failing rate of 250 minutes per inch (mpi) for the 38 inch boring and a failing rate of 150 mpi for the 84 inch deep boring onc4uenntly. these failing percolation rates require that the septic system for this project be engineered. LLPage-3- Chesney Consulting