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UEC Document No.: R3579901 February 8, 1999 The soil existing along the north side of the drainage pond was observed to have the same physical characteristics as the soil along the south side of the drainage pond. In summary, the soil down to a depth of 10 feet below grade observed in two of the four holes dug, consisted of primarily loam, with a small sand component; no clayey films or strata were observed. The physical properties of the soil along the north side of the drainage pond, including chemical and sieve analyses, may be found in Appendix E. The soils were observed to be uniform in color (medium brown) and texture. Soil Profile holes numbered 3 and 4 in Figure 3 contained a few stray roots between 2.0 and 3.0 feet below grade due to the close proximity of grape vines. No rock was observed in any of the four profile holes. Due to the recent rain in the subject site area, the uppermost 2.0-2.5 feet of soil had a higher moisture content then at deeper depths; no soil was observed to be in a saturated state. The two Soil Percolation tests were performed in strict adherence to the procedure set forth in Appendix A; as previously mentioned, the two Soil Percolation test holes were dug to a depth of 24 inches below grade with a backhoe, then advanced to a depth of 39 inches with a post hole digger. The average boring diameter for each of the two holes was 7.75 inches; the borings' walls were supported by 0.25" wire mesh in order to delay hole collapse. Two inches of fine gravel were put in place at the bottom of each of the borings. Rulers graduated in 0.25" intervals were established within the borings along the borings' walls; the rulers were held in place with duct tape and did not appear to move throughout the tests. Both holes were presoaked with 14" of clear water 24 hours prior to the commencement of the Soil Percolation test period. In both holes, it was observed that all of the presoak water had percolated into the soil throughout the evening; there was no water observed in either hole the following morning; the Soil Percolation Test Data may be found in Appendix D. Soil Percolation test hole #4 appeared to be nearly identical in appearance to Soil Percolation test hole #3; however, the percolation test data collected from hole #4 became skewed due to silting. Two hours into the Soil Percolation test at hole#4, the sides and edges of the hole were observed to have collapsed inward. At the end of the test, the UEC staff measured over 2 inches of silt at the bottom of he hole. The effect of the silting is to reduce the percolation rates and give the appearance that the soil does not percolate as well as it actual does. If and when a septic system is to be installed in this area, the leach lines should contain granular annular seals to help prevent the leach holes from filling with silt. The calculated percolation rates _ for hole #4 are based on data collected from the next to last timed interval. During that 30 minute time period, the water level was observed to drop 0.13", resulting in a percolation rate of 0.0043 inches of water per minute or 230.8 minutes per inch of water. As previously noted, this rate is believed to be artificially low due to the silting of the Soil Percolation test hole. 3