Current through March 20, 2024
Authority: IC 14-10-2-4; IC 25-39-4-2; IC 25-39-4-9
Affected: IC 25-39
Sec. 3.
(a) This
section establishes standards for monitoring wells that are in addition to the
general requirements for drilling a well under this article.
(b) A monitoring well shall be equipped with
casing. The composition, wall thickness, and nominal diameter of the casing
shall be sufficient to allow the well to be used for its intended
purpose.
(c) Monitoring well casing
shall be new first class material that meets the American Society of Testing
Materials (ASTM) standards ASTM A-120 (1984) or ASTM A-53 (1987) or the
American Petroleum Institute (API) standards API-5A or API-5L (1987).
Thermoplastic pipe shall comply with ASTM F-480 (1981). Well casing shall be as
follows:
(1) Clean and free of rust, grease,
oil, or contaminants and composed of materials that will have minimal impact on
the quality of a water sample.
(2)
Centered in the borehole and free of obstructions so monitoring devices can be
lowered into the well.
(d) A monitoring well screen shall be
composed of materials that will not corrode or react with chemicals found in
the ground water at the site. The well screen slots shall not be hand cut and
shall be sized to retain at least ninety percent (90%) of the grain size of the
introduced filter pack or natural formation materials if an introduced filter
pack is not used. The introduced filter pack shall:
(1) be properly sized and graded;
and
(2) not extend more than two
(2) feet above the top of the screen or the uppermost water bearing unit to be
monitored in the well annulus unless otherwise approved by the
division.
(e) A filter
pack seal of bentonite slurry or granular, pelletized, medium grade, or coarse
grade crushed bentonite may be placed in the annulus directly above the filter
pack or sand grout barrier. The filter pack seal shall:
(1) be installed to prevent bridging;
and
(2) not extend more than two
(2) feet above the filter pack or sand grout barrier.
(f) Except as provided in subsection (h), the
finished well casing:
(1) shall extend at
least two (2) feet above the ground level; and
(2) if located in a flood plain, must be:
(A) at least two (2) feet above the elevation
of the regulatory flood; or
(B)
equipped with a watertight cap.
The monitoring well shall be located to protect against
surface water ponding, and earthen materials, neat cement, or concrete shall be
placed around the well casing to drain surface water from the
well.
(g) A monitoring well, located where the
casing is susceptible to damage, shall be equipped with a protective outer pipe
consisting of a metal casing having a diameter large enough to allow easy
access to the well. The protective cover pipe shall be firmly anchored in the
ground. Additional protective devices, for example, brightly colored posts
around the well, are required where construction equipment or vehicular traffic
could damage the well.
(h) A
monitoring well must be equipped with a locking cap or cover to prevent
unauthorized access. The locking cap may be placed:
(1) directly on the well casing; or
(2) if required under subsection (g), on the
protective cover pipe.
(i) A monitoring well installed so that the
top of the well casing is finished at an elevation below the ground surface
shall be equipped with a watertight cap. The top of the well casing shall
terminate at a depth no greater than one (1) foot below the ground surface and
shall be located in a flush mounted protective cover pipe. The flush mounted
protective cover pipe shall include each of the following:
(1) A watertight one (1) piece or continuous
welded metal casing:
(A) at least one (1) foot
long; and
(B) having a nominal
diameter at least four (4) inches greater than the nominal diameter of the
monitoring well. The casing shall be flanged for greater stability if installed
in a location likely to be subject to vehicular traffic.
(2) A concrete ground surface seal, if an
impervious surface, for example, concrete or asphalt, is not present. The
ground surface seal shall be installed and extend not more than three (3) feet
below the ground surface.
(3) A
sealed lid that is not more than one-half (½) inch higher than the
elevation of the ground surface. The sealed lid shall be as follows:
(A) Of a quality to withstand vehicular
traffic if installed in a location likely to be subject to vehicular
traffic.
(B) Clearly marked with
the words "MONITORING WELL" or "MONITOR" and also display the words "DO NOT
FILL".
(j) A
monitoring well installed by the rotary or auger drilling method shall have a
borehole with a diameter at least two (2) inches greater than the nominal
diameter of the casing. Except as provided in subsection (e), the well shall be
grouted as follows:
(1) Granular bentonite may
be used to grout a monitoring well if the:
(A)
diameter of the borehole is four (4) inches or larger than the nominal diameter
of the well casing; and
(B) well is
not more than twenty-five (25) feet deep.
(2) Except as provided in subdivision (3),
the annulus of the monitoring well shall be pressure grouted with neat cement
or a bentonite slurry or be grouted with pelletized, medium grade, or coarse
grade crushed bentonite from the top of the filter pack or filter pack seal
under subsection (e) (for a well installed in unconsolidated materials) or the
bottom of the well casing (for a well penetrating bedrock) to the ground
surface or to within one (1) foot of the ground surface if a flush mounted
protective cover pipe is installed if the:
(A) diameter of the borehole is four (4)
inches or larger than the nominal diameter of the well casing; and
(B) well is not more than one hundred (100)
feet deep.
(3) The
annulus of the monitoring well shall be pressure grouted with neat cement or a
bentonite slurry from the top of the filter pack or filter pack seal under
subsection (e) (for a well installed in unconsolidated materials) or the bottom
of the well casing (for a well penetrating bedrock) to the ground surface or to
within one (1) foot of the ground surface if a flush mounted protected cover
pipe is installed where either the:
(A)
diameter of the borehole is less than four (4) inches larger in diameter than
the nominal diameter of the well casing; or
(B) well is more than one hundred (100) feet
deep.
(k) A
monitoring well installed by the cable tool method shall be grouted as follows:
(1) The well casing shall be centered in a
borehole:
(A) with a diameter of at least two
(2) inches greater than the nominal diameter of the casing to be
driven;
(B) dug at least three (3)
feet, but not more than five (5) feet, below the ground surface; and
(C) filled with granular bentonite or a
bentonite slurry during the installation of the casing. Notwithstanding
312 IAC
13-5-1(c), bentonite slurry may be
introduced into the borehole annulus by gravity methods during the installation
of the well casing.
(2)
Grouting shall be performed as provided under subsection (i) if a larger
diameter:
(A) temporary casing is used to
install a smaller diameter permanent well casing; or
(B) borehole is drilled to install a smaller
diameter well casing.
(l) A monitoring well installed by the direct
push method must be constructed as follows:
(1) The well shall be equipped with a
prepacked well screen.
(2) A sand
grout barrier shall:
(A) be placed directly
above the prepacked well screen in the annulus between the well casing (riser
pipe) and the borehole wall as the probe rods are retracted;
(B) be installed to prevent bridging;
and
(C) extend not more than two
(2) feet above the top of the prepacked well screen.
(3) A filter pack seal may be installed under
subsection (e) directly above the sand grout barrier.
(4) The remaining annulus between the well
casing (riser pipe) and probe rods shall be pressure grouted with neat cement
or a bentonite slurry from the top of the sand grout barrier or filter pack
seal to:
(A) if a flush-mounted protective
pipe is installed, within one (1) foot of the ground surface; or
(B) the ground surface.
(5) The probe rods shall be pulled during
installation of the grout material.
(m) A monitoring well shall be developed
following installation and before water samples are collected. This development
shall be accomplished to produce water that is as free as practicable from the
following:
(1) Sediment.
(2) Drill cuttings.
(3) Drilling fluids.
If a well is installed to monitor ground water quality, the
well shall be adequately developed to present a representative sample of the
water quality.
(n)
Contaminated drill cuttings, fluids, and surge and wash waters produced in the
drilling and development of a monitoring well shall be collected and contained
to:
(1) prevent contamination of the area;
and
(2) protect persons who might
otherwise come in contact with these materials.
(o) Monitoring well construction and
development equipment that comes in contact with contaminated water or
contaminated geologic materials shall be cleaned with high-pressure hot water
or steam, using inorganic soap or other suitable solvents, and rinsed
thoroughly. Contaminated fluids or wash waters shall be collected and contained
so that the result is not:
(1) contamination
of the area; or
(2) a hazard to
individuals who may come in contact with these
materials.