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Well Installations in Overburden Soils Paragon typically directs the drilling subcontractor to construct monitoring wells from two-inch diameter, flush joint threaded, schedule 40 polyvinyl chloride (PVC) casing and 0.010" PVC slotted screen. However, we may use larger or smaller diameter PVC as Site conditions warrant. We generally install a ten-foot section of well screen at the bottom of the well, with at least 2-8 feet of screen extending into the unsaturated zone, depending on anticipated seasonal water table elevation fluctuations. We fit the bottom of the well screen with a threaded or slip-on plug, and the top of the well casing with a watertight locking well cap. We include boring logs as report appendices that provide specific details regarding each monitoring well we install. Paragon directs the drilling subcontractor to advance soil borings in accordance with our "Soil Borings in Overburden Soils Protocol." We then direct them to filter-pack the annular space around the well to approximately 1-2 feet above the screen with clean sand. We generally use No. 2 (>0.01" grain size) silica sand for this purpose but may use other types of filter pack as appropriate for the well screen slot size. We then seal each well with 6-12 inches of bentonite clay above the sand pack, and backfill the annular space above the bentonite seal with clean soil cuttings or clean sand. Paragon usually installs flush-mounted roadway box sealed in place with concrete to protects the top of each well from damage, surface water infiltration, tampering, and vandalism. However, we may elect to use a lockable steel standpipe to protect monitoring wells that we install in open fields or heavily vegetated areas.