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Fteld Practtces and Procedures Page 4 The hydropunch is typically used with a drill rig A boring is drilled with hollow stem- augers to just above the sampling zone In some soil conditions the drill rig can push directly from the surface to the sampling interval The hydropunch is conveyed to the bottom of the boring using drill rods Once on bottom the hydropunch is driven a maximum of five feet The tool is then opened by lifting up the drill rod no more than four feet Once the tool is opened, water enters and a sample can be collected with a bailer or tubing utilizing a peristaltic pump Soil particles larger than silt are prevented from entering the tool by a screen within the tool The water sample is collected, labeled, and handled according to the Quality Assurance Plan Monitoring Well Installation Monitoring wells will be completed by installing 2- to 6-inch-diameter Schedule 40 polyvinyl chloride (PVC) casing The borehole diameter for a monitoring well will be a minimum of four inches larger than the outside diameter of the casing The 2-inch-diameter flush-threaded casing is generally used for wells dedicated for ' groundwater monitoring purposes A monitoring well is typically cased with threaded, factory-perforated and blank Schedule 40 PVC The perforated interval consists of slotted casing, generally with 0 01 or 0 02 inch-wide by 15-inch-long slots, with 42 slots per foot The screened sections of casing are factory machine slotted and will be installed approximately 5 feet above and �i 10 feet below first-encountered water level The screened interval will allow for seasonal fluctuation in water level and for monitoring floating product A threaded or slip PVC cap is secured to the bottom of the casing The slip cap can be secured with stainless steel screws or friction, no solvents or cements are used Centering devices may be fastened to the casing to ensure even distribution of filter material and grout within the borehole annulus The well casing is thoroughly washed and/or steam cleaned, or may be ' purchased as pre-cleaned, prior to completion A filter pack of graded sand will be placed in the annular space between the PVC casing ' and the borehole wall Sand will be added to the borehole through the hollow stem of the augers to provide a uniform filter pack around the casing and to stabilize the borehole The sand pack will be placed to a maximum of 2 feet above the screens, followed by a ' minimum 1-foot seal consisting of bentonite pellets Cement grout containing 5 percent bentonite or concrete will be placed above the ' bentonite seal to the ground surface A concrete traffic-rated vault box will be installed over the monitoring well(s) A watertight locking cap will be installed over the top of the well casing Reference elevations for each monitoring well will be surveyed when more ' than two wells will be located on site Monitoring well elevations will be surveyed by a California licensed surveyor to the nearest 0 01-foot relative to mean sea level (MSL) Horizontal coordinates of the wells will be measured at the same time ' Exploratory boring logs and well construction details will be prepared for the final written report ' M\Field Practices�Ftcld P&P with CPT doe