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MW-1 which is downgradient of the underground fuel storage <br /> tank pit <br /> In order to enhance our understanding of subsurface soil <br /> texture configurations between wells MW-1 , MW-2 , and MW-3 , <br /> a geologic cross section has been prepared The cross <br /> section, reproduced as Figure A, below, reveals a coarse <br /> textured layer consisting of silts , silty sands , and sands <br /> showing continuity between the three monitoring wells The <br /> the top of this layer varies between approximately 6 5 and <br /> 11 0 feet bgs , and slopes towards MW-1 from both MW-2 and <br /> MW-3 We believe that shallow groundwater is confined to <br /> this coarser layer with a capillary fringe extending upward j <br /> into a clayey (CL) layer <br /> Figure A <br /> Geologic ( Soil Profile) Cross Section <br /> 2360 East Street , Tracy, CA <br /> Mw-3 MW-2 <br /> MW-I v\ <br /> v O' <br /> CL Clays <br /> MH Silts, Sandy Silts <br /> ML Silts,Fine Sands ML 2 <br /> SC Clayey Sands <br /> Well-graded Sands <br /> 4 <br /> Horizontal Scale 1" - 25' C' 6 <br /> vertical Scale 1" - V <br /> 8 <br /> 10 <br /> SFS i I 12 <br /> MH i ML <br /> 1 I 1 , � 14 <br /> CL /I I <br /> 16 <br /> 18 <br /> CL <br /> 20 <br /> f 22 <br /> On page 7 of their report of February 14 , 1992 , the Resna <br /> Corporation stated that "Vertical migration of contaminants <br /> appears to have been fairly rapid with little spreading" . <br /> EPM concurs that migration in the CL layer will be <br /> reasonably vertical down to the capillary fringe However , <br /> Page 11 <br />