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WKERNO-My <br /> RRN <br /> ,a <br /> �- layer, apparently discontinuous and more variable, was encountered in 3 of the CPT <br /> soundings at a depth of approximately 10 feet below ground level. This data is consistent <br /> T with the soil type descriptions contained in the drilling logs for monitoring wells <br /> installed on the site. The CPT data, however, is believed to provide higher resolution <br /> data since it is obtained continuously versus depth while the drilling logs were based on <br /> samples obtained at 5 toot intervals. In addition the CPT test data provides a more <br /> objective assessment of stratigraphy than that obtained solely from visual observations of <br /> soil samples. <br /> 4.1.2 Inferred Depth to Groundwater <br /> Pore pressure dissipation tests were conducted at each CPT location, generally at multiple <br /> depths within each sounding. The inferred depth to groundwater is obtained by subtracting <br /> the projected equilibrium pore pressure (equivalent height of water column above the <br /> transducer) from the dspth of the transducer below ground level. The accuracy of these <br /> measurements,a function of the transducer range and depth measurement,is believed to be <br /> approximately±1.5 feet. However,accuracy may be less than this when the transducer is <br /> subjected to low pressures. <br /> Dissipation test data, obtained when the test duration was sufficient to project an <br /> equilibrium pore pressure, contained apparent iinomalies with inferred depth to water <br /> measurements ranging from 8.5 feet to 20 feet below ground level. Depth to water <br /> measurements obtained by depth discrete techniques, including the CPT test, may not <br /> - compare directly with monitoring well data where monitoring wells are completed over broad <br /> intervals in non-homogeneous soils. Monitoring wells completed in these conditions may <br /> - yield composite or averaged water levels. <br /> 4.1.3 Permeability <br /> Values for horizontal permeability were calculated where sufficient dissipation test data <br /> was obtained. These tests indicated a range of permeability from 8.5E-06 to 4.3E-08 <br /> cm/sec for the soil types tested at depths of 24.4 to 30.5 feet below ground level. These <br /> results are consistent with the typical range of permeabilkies for naturally deposited <br /> fine sands and silts. <br /> 13 <br />