Administrative Rules of Montana › Department 17 - ENVIRONMENTAL QUALITY › Chapter 17.30 - WATER QUALITY › Subchapter 17.30.6 - Surface Water Quality Standards and Procedures › Rule 17.30.602 - DEFINITIONS

Current through Register Vol. 13, July 5, 2024
In this subchapter the following terms have the meanings
				  indicated below and are supplemental to the definitions given in
				  75-5-103, MCA:
(1) "Bioconcentrating parameters" means the
				parameters listed in department Circular DEQ-7 which have a bioconcentration
				factor greater than 300.
(2)
				"Carcinogenic parameters" means the parameters categorized as carcinogens in
				department Circular DEQ-7.
(3)
				"Chlorophyll a" means the mass of chlorophyll a pigment after correction for
				phaeophytins.
(4) "Conduit" means
				any artificial or natural duct, either open or closed, capable of conveying
				liquids or pollutants.
(5)
				"Conventional water treatment" means in order of application the processes of
				coagulation, sedimentation, filtration, and disinfection. If determined
				necessary by the department it also includes taste and odor control and lime
				softening.
(6) "Dewatered stream"
				means a perennial or intermittent stream from which water has been removed for
				one or more beneficial uses.
(7)
				"Electrical conductivity (EC)" means the ability of water to conduct an
				electrical current at 25°C. The electrical conductivity of water represents
				the amount of total dissolved solids in the water and is expressed as
				microSiemens/centimeter (µmhos/cm) or micromhos/centimeter (µS/cm)
				or equivalent units and is corrected to 25°C.
(8) "Discharge" means the injection, deposit,
				dumping, spilling, leaking, placing, or failing to remove any pollutant so that
				it or any constituent thereof may enter into state waters, including ground
				water.
(9) "EPA" means the US
				Environmental Protection Agency.
(10) "Ephemeral stream" means a stream or
				part of a stream which flows only in direct response to precipitation in the
				immediate watershed or in response to the melting of a cover of snow and ice
				and whose channel bottom is always above the local water table.
(11) "Geometric mean" means the value
				obtained by taking the Nth root of the product of the measured values where
				zero values for measured values are taken to be the detection limit.
(12) "Harmful parameters" means parameters
				listed as harmful in department Circular DEQ-7.
(13) "Intermittent stream" means a stream or
				reach of a stream that is below the local water table for at least some part of
				the year, and obtains its flow from both surface run-off and ground water
				discharge.
(14) "Mixing zone" is
				defined in
				75-5-103, MCA, and also means a
				limited area of a surface water body or a portion of an aquifer, where initial
				dilution of a discharge takes place and where water quality changes may occur
				and where certain water quality standards may be exceeded.
(15) "MPDES" means the Montana pollutant
				discharge elimination system.
(16)
				"NPDES" means the national pollutant discharge elimination system.
(17) "Naturally occurring" means conditions
				or material present from runoff or percolation over which man has no control or
				from developed land where all reasonable land, soil and water conservation
				practices have been applied. Conditions resulting from the reasonable operation
				of dams in existence as of July 1, 1971, are natural.
(18) "Nonpoint source" means the source of
				pollutants which originates from diffuse runoff, seepage, drainage, or
				infiltration.
(19) "Outstanding
				resource water" or "ORW" has the meaning set out in
				75-5-103, MCA.
(20) "Pesticide" means insecticides,
				herbicides, rodenticides, fungicides, or any substance or mixture of substances
				intended for preventing, destroying, controlling, repelling, altering life
				processes, or mitigating any insects, rodents, nematodes, fungi, weeds, and
				other forms of plant or animal life.
(21) "Phaeophytins" means the degradation
				products of chlorophyll.
(22)
				"Pollutants" means sewage, industrial wastes, and other wastes as those terms
				are defined in
				75-5-103, MCA.
(23) "Reasonable land, soil, and water
				conservation practices" means methods, measures, or practices that protect
				present and reasonably anticipated beneficial uses. These practices include,
				but are not limited to, structural and nonstructural controls and operation and
				maintenance procedures. Appropriate practices may be applied before, during, or
				after pollution-producing activities.
(24) "Seasonal lake or pond" means a natural
				depression in the land surface that periodically holds water from precipitation
				or snow and ice melt in the immediate watershed.
(25) "Sodium adsorption ratio (SAR)" means a
				value representing the relative amount of sodium ions to the combined amount of
				calcium and magnesium ions in water using the following formula: SAR =
				[Na]/(([Ca]+[Mg])/2)½ , where all
				concentrations are expressed as milliequivalents of charge per liter.
(26) "Secondary contact recreation" means
				activities in or on the water where the potential for immersion or ingestion of
				water is low, such as wading or boating.
(27) "Sediment" means solid material settled
				from suspension in a liquid; mineral or organic solid material that is being
				transported or has been moved from its site of origin by air, water, or ice and
				has come to rest on the earth's surface, either above or below sea level; or
				inorganic or organic particles originating from weathering, chemical
				precipitation, or biological activity.
(28) "Semi-permanent lake or pond" means a
				natural depression in the land surface, not including reservoirs, that receives
				ground water in addition to precipitation runoff from the immediate watershed,
				and occasionally goes dry.
(29)
				"Settleable solids" means inorganic or organic particles that are being
				transported or have been transported by water from the site or sites of origin
				and are settled or are capable of being settled from suspension.
(30) "Sewer" means a pipe or conduit that
				carries wastewater or drainage water.
(31) "Surface waters" means any waters on the
				earth's surface including, but not limited to, streams, lakes, ponds, and
				reservoirs; and irrigation and drainage systems discharging directly into a
				stream, lake, pond, reservoir, or other surface water. Water bodies used solely
				for treating, transporting, or impounding pollutants shall not be considered
				surface water.
(32) "Storm sewer"
				or "storm drain" means a pipe or conduit that carries storm water and surface
				water and street washings.
(33)
				"Total nitrogen" means the sum of all nitrate, nitrite, ammonia, and organic
				nitrogen, as N, in an unfiltered water sample. Total nitrogen in a sample may
				also be determined by the persulfate digestion or as the sum of total kjeldahl
				nitrogen plus nitrate plus nitrite.
(34) "Total phosphorus" means the sum of
				orthophosphates, polyphosphates, and organically bound phosphates, as P, in an
				unfiltered water sample. Total phosphorus may also be determined directly by
				persulfate digestion.
(35) "Toxic
				parameters" means those parameters listed as toxins in department Circular
				DEQ-7.
(36) "True color" means the
				color of water from which the turbidity has been removed.
(37) "Turbidity" means a condition in water
				or wastewater caused by the presence of suspended matter resulting in the
				scattering and absorption of light rays.
(38) "Use attainability analysis" means a
				scientific assessment and analysis of the factors affecting the attainment of a
				use(s). Information that may be used include chemical, physical and biological
				data, as well as photo documentation and comparison to reference conditions,
				that are of sufficient detail to accurately portray the level and potential
				level of use support of a waterbody. The use attainability analysis is required
				by the US EPA according to 40 CFR 131.10 (g), (h) and
				(j).
(39) "DEQ-7" means the
				department circular that is adopted and incorporated by reference in ARM
				17.30.619 and is entitled "Montana
				Numeric Water Quality Standards." This circular establishes water quality
				standards for toxic, carcinogenic, bioconcentrating, radioactive, and harmful
				parameters, and also establishes human health-based water quality standards for
				the following specific nutrients with toxic effects:
(a) nitrate;
(b) nitrate + nitrite; and
(c) nitrite.