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deep enough to encounter horizons 4 and 5. No specific laboratory or field <br />test results were reported to establish hydraulic conductivity of any of <br />the subsurface soil horizon. From our previous investigations in the Delta <br />region, however, we anticipate that hydraulic conductivities of individual <br />soil layers to range from 10 -2 to 10-5cm/sec. <br />Groundwater level measurements in the on—site monitoring wells are <br />used to develop the groundwater table map of Drawing 3. This map indicates <br />a horizontal groundwater gradient of approximately 0.01 to 0.04 from the <br />central portions of the site to northern and southern ends of the site. <br />• <br />Assuming a hydraulic conductivity (permeability) of 10 -3 cm/sec and an <br />effective porosity of 0.2 for the subsurface soils, the velocity of fuel <br />products would be approximately lo cm/day or 0.3 foot/day. It should be <br />noted that this is a very rough estimation and localized flow rates can <br />easily be higher or lower by an order of magnitude. However, these <br />approximations suggest that fuel products on the groundwater table can <br />migrate at a rate of approximately 10 feet per month. <br />2.5 Spill Description <br />The, pipeline section where the leakage is suspected to have occurred <br />is 10 inches in diameter and is subject to a normal operating pressure of <br />1000 :t'o 1300 psi. Drawing 2 shows the locations of the pipeline suspected <br />of leakage, the newly installed bypass and the twelve monitoring wells. <br />The section of pipeline replaced is approximately 530 feet long. In any <br />one week the pipeline may convey gasoline (leaded and unleaded), diesel <br />fuel, JP4, and turbine fuel in various quantities. <br />In January 1986 the following fuel quantities were conveyed through <br />the pipeline over a 4 cycle period: <br />2-4 <br />urn