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7theater infiltrated and percolated-through this sand stratum, thus exhibiting an excellent <br /> f 6.3 min/in. Since the 12 ft boring did not extend down into this sand stratum, this <br /> recorded a final perc rate of 83 min/in. <br /> HYDRAULIC CONDUCTIVITY TEST <br /> As referenced on the Log of Boring, the subsurface soils consist predominately of finer-sized silt <br /> and clay particles. The hydraulic conductivity (K) of the vadose zone (subsurface soils) <br /> determines the potential for water infiltration into the embankments and floor of the holding <br /> pond and consequently the downward flow characteristics of water. To quantify this parameter, <br /> the Shallow-Well Pump-In Test Method(Soil Science Society of America)was employed. The <br /> test was conducted adjacent to the west of the holding pond, 20 ft northeast of the 45 ft deep <br /> exploratory boring. The test boring was drilled down to 10 ft below grade. A constant level of <br /> water was supplied to the boring, to a height of 9 ft. The rate at which water flowed into the soil <br /> (Q) was determined to be 1,200 cc/hr after the four-hour test. Although the soil characteristics <br /> are relatively constant the entire length of the test boring, an average hydraulic conductivity is <br /> obtained by this method. The equation to determine the hydraulic conductivity in cm/hr is as <br /> follows: <br /> K= 3 In h/r <br /> f 11 h(h+2T.) <br /> Where: <br /> h= 9 ft (274.3 cm) <br /> r=0.67 ft(20.4 cm) <br /> Q = 1,200 cc/hr <br /> T.— 9 ft (274.3 cm) <br /> Therefore, K= 0.0132 cm/hr (3.7 x 10' cm/s) <br /> These test results show the hydraulic conductivity of the subsoil silt strata possess a <br /> com arati slypermeability and suggest it would theoretically take a water molecule <br /> approximately 9,141 days or 25 years to travel from near the soil surface to the water table, --95 <br /> ft below grade. Summarization of the physical soil tests: <br /> PERCOLATIO?N/H"RAULIC CONDUCTMTY TEST RESULTS <br /> PERC TEST PERC RATE IN MINANCH <br /> Leachline depth-42 inches. Initial Test 0 min/in-Failed <br /> Leachline depth-42 inches. Second Test 15 min/in <br /> Sump depth- 12 ft 83 min/in <br /> Seepage pit-23 ft 6.3 min/in <br /> Hydraulic Conductivity Test- 10 ft deep 0.0132 cm/hr <br /> 5 <br /> x` valley Ag Research- <br />