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ERDC/CRREL TR-02-1
observation well equipped with a 1.5- to 2.0-m screen is installed at each moni-
toring point. The maximal depth of drilling is related to the depth of the ground-
water at the specific site. The well's components (well casing, joints, screen,
filtering pack, expansive cement, cement/bentonite mix or bentonite silt, protec-
tive casing), its dimensions, and its installation must be in accordance with
ASTM-D5092-90. Installation of the wells is also described in the Natural Atten-
uation Protocol (Pennington 1996). No other seal material than those required by
the guideline or by the standards should be used in the space between the perma-
nent well casing and the borehole wall. The permanent casing and screen of the
well should be made of PVC with 1.5- to 2.0-m well screens. Well elevation must
be established from the top of the PVC permanent casing. The borehole
locations, depth of drilling, local geological stratigraphy (drilling log), identifi-
cation of the drilling method used, and the specifications related to the installa-
tion of the well are then recorded. A protective casing with locks should be
installed on each well. This is intended to protect the well from outside contam-
ination as well as from mechanical shock. Additional protection can be gained by
installing a concrete pad at the surface around the wellhead.
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