Laserfiche WebLink
sufficient areal coverage to allow for the determination of an accurate <br /> groundwater flow direction and gradient for the site. <br /> Water levels will be measured to confirm the groundwater gradient <br /> and direction of groundwater flow. Groundwater samples will be <br /> collected for laboratory analysis. <br /> Soil sampling at each monitoring well boring will be performed for <br /> logging purposes and to determine accurate placement of the screened <br /> interval. Since the majority of monitoring wells will be located outside <br /> the area of contamination, laboratory analysis of the soil samples will <br /> be used primarily to determine proper disposal of drill cuttings. <br /> Well Bore Installation <br /> Three well bores will be installed at each site with a mobile drill rig <br /> using hollow-stem augers. Soil samples will be collected at <br /> approximate five-foot intervals or at significant lithologic changes and <br /> will continue to groundwater. The soils from these borings will be <br /> logged according to the USCS (Appendix A). The drilling logs will be <br /> based upon information obtained from drill cuttings, actual soil <br /> samples, and changes in drilling characteristics. <br /> Drill Cutting Disposition <br /> Drill cuttings will be contained in 55-gallon drums and stored on site in <br /> a temporary fenced enclosure pending review of the sample analytical <br /> results. All drums will be marked clearly with labels stating date of soil <br /> collection and the phrase "Pending Analytical Results." Arrangement <br /> will then be made for off-site disposal of any fuel-affected cuttings. If <br /> the drill cutting soil is determine to be clean, arrangements will be <br /> made to either dispose of the soil on-site or transport to an acceptable <br /> landfill. <br /> Monitoring Well Construction. <br /> A typical monitoring well design is shown in Appendix B. The well <br /> bore will be drilled with a mobile drill rig using hollow-stem augers. <br /> Depths of the wells may vary with each site and are expected to be <br /> between 15 and 20 feet bgs. Slotted PVC and blank PVC casing will be <br /> inserted into the well bore. Filter pack sand will be poured into the <br /> annular space around the slotted PVC as the augers are removed. The <br /> filter pack will extend one to two feet above the top of the slotted PVC. <br /> One to two feet of bentonite pellets will be placed on top of the filter <br /> 4-6 <br />