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!1 T A silt strata to depths of 19 to 24 feet These strata compose the uppermost aquifer strata Clayey • sand and silty clay underlie the aquifer strata These clayey strata appear laterally discontinuous in the general area of the site investigation (see Figures 1 and. 2) Groundwater occurs at depths of 15 S to 16 feet and appeared to be unconfined however boreholes were not open long enough to allow for 24 hours of stabilization for additional groundwater measurements Strata may grade laterally and vertically in the region and is typical San Joaquin Valley sediment depositional environments (see Geologic Cross section, figure 2) The site borehole data Indicate that the uppermost shallow aquifer and underlying aquitard have some lateral continuity but are assumed to leak Physical Analysis One soli sample from Boring B-3 at 19-20 feet was sent to Earthtec Ltd for physical analysis The laboratory report is attached and the results are presented below in Table 1 Table 1. Physical Analysis SAMPLE ORGANIC SPECIFIC MOISTURE DRY UNIT HYDRAULIC POROSITY 13ULK • CARBON GRAVITY CONTENT WEIGHT CONDUCTIVITY DENSITY % % Pcf Cm/sec % Pcf B-30)19-20' 006 2 772 1 1640 1 1169 1 1x 10-71 1 36 132 1 Pcf—Pounds per cubic foot Cm/sec—Centimeters per second The test results show that the sample is clayey sand with a low hydraulic conductivity The sample was collected from the lower portions of the aquifer and the aquifer sand content increases in depth at some locations the site This sample was collected across a transitional contact with the underlying aquitard that is interpreted to account for the low conductivity (grading into more clay with depth at this location) Clay dispersed In the aquifer strata sand would also lower conductivity, however the aquifer strata with higher sand content are assumed to have somewhat higher hydraulic conductivity. Borehole logging in other boreholes shows that the aquifer is predominantly composed of sandy strata that should have a higher hydraulic conductivity The aquifer-aquitard transition is interpreted to have low conductivity with depth into the aquitard The organic carbon content is very low when compared to typical surface or near surface soil (uppermost three to five feet) Organic carbon decays through oxidation and burial depth in geologic deposits In our opinion, given the depth of these sediments, the organic carbon content is considered negligible The porosity and density data for the sample are considered in the range of clayey sand soil c}