Mont. Admin. R. 36.21.634 - DEFINITIONS
For purposes of this chapter, the following terms shall apply.
(1) "Abandoned water well":
(a) "permanent" means a well whose use has
been permanently discontinued; and
(b) "temporary" means a well from which a
drilling rig has been removed from the well site prior to completing or
altering the well.
(2)
"Access port" means an opening in the upper terminus of a well casing in the
form of a tapped hole and plug or a capped pipe welded onto the casing to
permit entry of water-level measuring devices into the well.
(3) "Annular space" or "annulus" means the
space between a drill hole and a casing pipe, or between two well casings.
(4) "Aquifer" means any geological
formation which is capable of yielding water or is capable of recharge.
(a) Any discrete water bearing unit with a
specific water chemistry, temperature, or hydrostatic head shall be considered
a separate aquifer.
(5)
"Artesian well" means a well in which the water level rises above the point at
which it was first encountered. This term includes both flowing and non-flowing
wells.
(6) "Bentonite" means a
highly plastic, highly absorbent, colloidal clay composed primarily of swelling
sodium montmorillonite.
(7) "Board"
means the Montana Board of Water Well Contractors.
(8) "Capped well" means a well that is not in
use and has a permanent seal or locked cap installed on top of the casing.
(9) "Casing":
(a) "inner" means the inner tubing, pipe, or
conduit installed inside the well casing or lower well drill hole, which is
used to protect against caving formations or to seal out polluted or
mineralized water zones; and
(b)
"outer" means an impervious durable pipe placed in a well to:
(i) prevent the walls from caving;
(ii) seal off surface drainage or undesirable
water, gas, or other fluids to prevent their entering the well; and
(iii) prevent the waste of
groundwater.
(10) "Casing seal" means the watertight seal
established in the drill hole between the well casing and the drill hole wall
to prevent the inflow and movement of surface water or shallow ground water in
the well annulus, or to prevent the outflow or movement of water under artesian
or hydrostatic pressures.
(11)
"Clay" means a fine-grained, inorganic material having plastic properties and
with a predominant grain size of less than 0.005 mm (0.0002 inches).
(12) "Community water system" means any
public water supply system which serves at least 15 service connections used by
year-round residents or regularly serves at least 25 year-round residents.
(13) "Concrete" means a mixture of
not more than two parts sand and one part cement, and not more than six gallons
of clear water per 94-pound bag of Portland cement. Up to five percent, by
weight, of bentonite clay may be used to improve flow and reduce shrinkage.
(14) "Confining formation" means a
body of impermeable or distinctly less permeable material adjacent to one or
more aquifers.
(15) "Consolidated
formation" means any geologic formation in which the earth materials have
become firm and coherent through natural rock forming processes, including, but
is not limited to basalt, granite, sandstone, shale, conglomerate, and
limestone.
(16) "Construction of
water wells" means all acts necessary to obtain groundwater by wells,
including:
(a) the contracting for, and
excavation of the well;
(b)
installation of casing, sealing material, and screens; and
(c) developing and testing, whether in the
installation of a new well or the alteration of an existing well. The term does
not include the installation of permanent pumps and pumping equipment.
(17) "Contamination"
means an impairment of water quality by chemicals, radionuclides, heat, or
biologic life to a degree that may or may not affect the potential or intended
use of water.
(18) "Department"
means the Department of Natural Resources and Conservation.
(19) "Disinfection" means the introduction of
chlorine or other disinfecting agents using a method approved by the board, in
a sufficient concentration and followed by an adequate exposure contact time so
as to inactivate coliform or other indicator organisms.
(20) "Drawdown" means the extent of lowering
of the water level in a well when pumping is in progress or when water is
discharging from a flowing well. Drawdown is the difference between the static
water level and the pumping level.
(21) "Gravel pack":
(a) "artificial gravel pack" means placement
of gravel in the annular space around the well casing or screen. A gravel pack
is frequently used to:
(i) prevent the
movement of finer material into the well casing;
(ii) increase the ability of the well to
yield water; and
(iii) lend
lateral support to screens in unstable formations; and
(b) "natural gravel pack" means a gravel pack
which leaves the coarser, naturally occurring gravels around the screen. The
finer sands are removed from the formation by development.
(22) "Monitoring well" means a well that will
be used for pollutant recovery or monitoring of groundwater quality,
groundwater levels, or flow direction but whose primary purpose is not
withdrawal or acquisition of groundwater.
(23) "Montana Bureau of Mines and Geology
(MBMG)" means the Montana Bureau of Mines and Geology located in Butte,
Montana.
(24) "Multiple-user water
supply system" means a nonpublic water supply system designed to provide water
for human consumption. In estimating the population served, the reviewing
authority shall multiply the number of living units based on the most recent
census data. The supply system shall provide water for:
(a) 3 through 14 living units; or
(b) 3 through 14 commercial units. The total
people served shall not exceed 24.
(25) "Noncommunity water system" means any
public water supply system which is not a community water system.
(26) "Pitless adapter or pitless unit" means
a commercially manufactured unit or device designed for attachment to a well
casing which permits buried pump discharge from the well and allows access to
the interior of the well casing for installation or removal of the pump or pump
appurtenances, while preventing the entrance of contaminants from surface or
near surface sources from entering the well.
(27) "Pollution" means a serious impairment
of water quality by chemicals, radionuclides, heat, biologic organisms, or
other extraneous matter to the degree that impairs the potential or intended
use of water or creates a hazard to the public health and safety.
(28) "Potable water" means water which is
safe for human consumption in that it is free from impurities in amounts
sufficient to cause disease or harmful physiological effects.
(29) "Public water supply system" means a
system for the provision of water for human consumption from any community
well, water hauler for cisterns, water bottling plant, water dispenser, or
other water supply that has at least 15 service connections or that regularly
serves at least 25 persons daily for any period of 60 days or more in a
calendar year.
(30) "Pump test"
means the procedure used to determine the yield characteristics of a water well
by installing and operating a pump for an extended period of time.
(31) "Pumps" and "pumping equipment" mean any
equipment or materials utilized or intended for use, including seals and tanks,
together with fittings and controls, in withdrawing or obtaining groundwater
for any use.
(32) "Sand" means a
detrital material having a prevalent grain size ranging from 2 millimeters to
0.06 millimeters (0.08 inch to 0.002 inch).
(33) "Sanitary well seal" means a
manufactured seal installed at the top of the well casing which, when
installed, creates a watertight seal to prevent contaminated or polluted water
from gaining access to the ground water supply.
(34) "Sealing material" means neat cement,
bentonite water slurry or grout, or bentonite chips or pellets. Bentonite water
slurry shall be mixed according to the manufacturer's instructions as a sealing
material, and shall contain no less than 1.5 pounds of bentonite per gallon of
freshwater. The mixed slurry shall weigh no less than nine pounds per gallon.
(a) "Bentonite clay grout" means a mixture
consisting of not less than one-half pound of commercial bentonite clay to one
gallon of clear water.
(b) "Neat
cement grout" means a mixture of not more than six gallons of clear water per
94-pound bag of Portland cement. Up to five percent, by weight, of bentonite
clay may be used to improve flow and reduce shrinkage. No sand or gravel is to
be used in cement grout.
(c) Any
slurry or cement shall be pumped from the bottom up. Chip or pellet placement
may be gravity fed at a controlled rate that equals or is slower than the
manufacturer's recommendation, and in such a manner that will prevent
bridging.
(35) "Sewage
lagoon" means any holding or detention pond that is used for treatment or
storage of water-carried waste products from residences, public buildings,
institutions, or other buildings, including discharge from human beings or
animals, together with ground water infiltration and surface water present. For
purposes of this rule, the term includes concentrated animal feeding operations
but does not include storm water facilities or subsurface wastewater treatment
systems.
(36) "Silt" means an
unconsolidated clastic sediment composed predominantly of particles between
0.06 and 0.005 mm (0.002 inch to 0.0002 inch) in diameter.
(37) "Static water level" means the vertical
distance from the surface of the ground to the water level in a well when no
water is being taken from the aquifer, either by pumping or by free flow.
(38) "Transient noncommunity water
system" means a public water supply system that is not a community water system
and that does not regularly serve at least 25 of the same persons for at least
six months per year.
(39)
"Unconsolidated formation" means naturally occurring, noncemented materials
including, but not limited to clay, sand, silt, and gravel.
(40) "Water table" means the upper surface of
an unconfined water body, the surface of which is at atmospheric pressure and
fluctuates seasonally.
(41) "Well
drilling machine" means any power-driven machine used in the construction or
alteration of water wells, including, but not limited to percussion, jetting,
rotary, boring, digging, or augering machines.
Notes
AUTH: 37-43-202, MCA; IMP: 37-43-202, MCA
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