Laserfiche WebLink
of unconsolidated fluvial sediments A layer of silty sand was noted between 18 and 25 feet <br /> below grade A layer of silt with varying concentrations of sand was noted from 25 to 30 <br /> feet below grade, the total depth explored Review of boring logs for wells MW-1, MW-2, <br /> and MW-3, installed surrounding the site in December 1991, indicates that a sand layer <br /> underlies the silt to 60 feet below grade, the total depth explored <br /> A particle size analysis (using the hydrometer method) was conducted on a sample collected <br /> at 28 5 feet below grade from well VW-A Results indicated the sample was composed of <br /> 66 1% fines and 33 9% coarse grained material, which can be described as brown silt slightly <br /> cemented using the Unified Soil Classification System (USCS) <br /> Boring Iogs for wells VW-A and VW-B can be found in Appendix A, the hydrometer test <br /> results can be found in Appendix C for reference <br /> 3.2 Site Hydrogeology <br /> No groundwater was encountered during this investigation, however, groundwater is known to <br /> exist at the site at a depth of approximately 41 feet below grade Groundwater flow vanes <br /> from east to northeast under a shallow gradient <br /> 3.3 Soil Quality Data <br /> In November 1993, three 25,000 gallon diesel USTs were removed from beneath the Lindsay <br /> Street sidewalk Analysis of verification soil samples collected November 10, 1993 revealed <br /> the presence of 2,900 ppm diesel in the sample collected at the west end of the middle tank <br /> (approximately 15 feet below grade) No detectable diesel or BTEX concentrations were <br /> encountered in the eight remaining verification samples <br /> The area was over excavated to 17.5 feet below grade and 10 venfication samples were <br /> collected on November 11, 1993 Analysis of these samples revealed diesel concentrations in <br /> the north (8200 ppm and 3300 ppm) and south (16000 ppm) limits of the newly excavated <br /> area. Two of the venfication samples were collected at approximately 20 feet below grade <br /> Analysis of these samples revealed a significant decrease in diesel concentrations (from 8200 <br /> ppm to 820 ppm - north sample and from 16000 ppm to 21 ppm - south sample) <br /> MV09-08-94/UST194-0142 nbr 7 <br />