(a) A monitoring well shall be cased as
follows:
(1) The casing shall maintain the
integrity of the monitoring well borehole and shall be constructed of material
that will not react with the groundwater being monitored.
(2) The minimum casing diameter shall be 4
inches unless otherwise approved by the Department in writing.
(3) The well shall be constructed with a
screen that meets the following requirements:
(i) The screen shall be
factory-made.
(ii) The screen may
not react with the groundwater being monitored.
(iii) The screen shall maximize open area to
minimize entrance velocities and allow rapid sample recovery.
(4) The well shall be
filter-packed with chemically inert clean quartz sand, silica or glass beads.
The material shall be well-rounded and dimensionally stable.
(5) The casing shall be clearly visible and
protrude at least 1 foot aboveground, unless the Department has approved flush
mount wells.
(6) The annular space
above the sampling depth shall be sealed to prevent contamination of samples
and the groundwater.
(7) The casing
shall be designed and constructed to prevent cross contamination between
surface water and groundwater.
(8)
Alternative casing designs for wells in stable formations may be approved by
the Department.
(b)
Monitoring well casings shall be enclosed in a protective casing that shall:
(1) Be of sufficient strength to protect the
well from damage by heavy equipment and vandalism.
(2) Be installed for at least the upper 10
feet of the monitoring well, as measured from the well cap, with a maximum
stick up of 3 feet, unless otherwise approved by the Department in
writing.
(3) Be grouted and placed
with a concrete collar at least 3 feet deep to hold it firmly in
position.
(4) Be numbered for
identification with a label capable of withstanding field conditions and
painted in a highly visible color.
(5) Protrude above the monitoring well
casing.
(6) Have a locked
cap.
(7) Be made of steel or other
material of equivalent strength.