Laserfiche WebLink
Geolagrta!'Iechiius 1nc - - - � - - - - - - - -- - - - -- - - - -Page 2 - <br /> Groundwater Monitoring Report <br /> Project No 425 2 <br /> June 9,2000 <br /> 5 <br /> • Vertical groundwater gradients do exist at the site and range from 2 to 20 times the <br /> magnitude of the horizontal gradient At times the site has experienced both a <br /> negative and positive vertical gradient <br />' 2 Groundwater Contamination <br /> • Floating product has routinely been detected in MW-2 (located in the area of the <br />' former USTs) during late fall and winter months However it has not been observed <br /> in the last few years <br /> • The contamination observed in MW-102 during 1997 and early 1998 has attenuated <br /> • The contamination observed in MW-202 has steadily decreased from the initial <br /> concentration observed after installation and was non-detect for all analytes during <br /> the December 1999 and March 2000 events <br /> • The domestic well at 1600"A" Durham Ferry Road detected trace concentrations of <br /> Benzene during the April 1999 event The well has been non-detect for the last three <br /> monitoring events so the benzene contamination was most likely due to cross <br />' contamination from the sampling technician or laboratory <br /> It is recommended that <br /> o Future monitoring should include a complete natural attenuation parameter analysis <br /> o This site should be evaluated for the need of source removal to provide needed protection <br /> to public health and the environment A remedial action alternative evaluation is being <br /> prepared and will be submitted shortly <br /> 1.0 GROUNDWATER MONITORING <br />' 1.1 Hydrology of Site <br /> 1.1.1 Horizontal Groundwater Gradients <br /> Water Table Wells <br /> The average water table elevation at the site in March was 72 32 feet above mean sea level <br /> i� and the water table groundwater gradient was 0 0016 ft/ft flowing N59°E A review of the <br /> groundwater gradients shows that the dominant groundwater flow is to the north with the <br /> slope ranging from 0 0012 up to 0 0289 ft/ft It is noted that the flow has been more easterly <br /> during the last two events Table 1 of Appendix A summarizes the water table groundwater <br /> gradients and levels to date <br /> 5' Intermediate & Deep Wells <br /> The average groundwater elevation in the intermediate depth wells (MW-102, MW-105 & <br /> i MW-107) for March was 72 25 feet above mean sea level and the intermediate depth <br /> groundwater gradient was 0 0018 ft/ft flowing N80°E <br />