Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 1 - WYOMING SURFACE WATER QUALITY STANDARDS
Section 1-2 - Definitions

(i) "Credible data" means scientifically valid chemical, physical and biological monitoring data collected under an accepted sampling and analysis plan, including quality control, quality assurance procedures and available historical data;

(ii) "Discharge" means any addition of any pollution or wastes to any waters of the state;

(iii) "Ecological function" means the ability of an area to support vegetation and fish and wildlife populations, recharge aquifers, stabilize base flows, attenuate flooding, trap sediment and remove or transform nutrients and other pollutants;

(iv) "Man-made wetlands" means those wetlands that are created intentionally or occur incidental to human activities, and includes any enhancement made to an existing wetland which increases its function or value;

(v) "Mitigation" means all actions to avoid, minimize, restore and compensate for ecological functions or wetland values lost;

(vi) "Natural wetlands" means those wetlands that occur independently of human manipulation of the landscape;

(vii) "Nonpoint source" means any source of pollution other than a point source. For purposes of W.S. 16-1-201 through 16-1-207 only, nonpoint source includes leaking underground storage tanks as defined by W.S. 35-11-1415(a)(ix) and aboveground storage tanks as defined by W.S. 35-11-1415(a)(xi);

(viii) "Point source" means any discernible, confined and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation or vessel or other floating craft, from which pollutants are or may be discharged;

(ix) "Pollution" means contamination or other alteration of the physical, chemical or biological properties of any waters of the state, including change in temperature, taste, color, turbidity or odor of the waters or any discharge of any acid or toxic material, chemical or chemical compound, whether it be liquid, gaseous, solid, radioactive or other substance, including wastes, into any waters of the state which creates a nuisance or renders any waters harmful, detrimental or injurious to public health, safety or welfare, to domestic, commercial, industrial, agricultural, recreational or other legitimate beneficial uses, or to livestock, wildlife or aquatic life, or which degrades the water for its intended use, or adversely affects the environment. This term does not mean water, gas or other material which is injected into a well to facilitate production of oil, or gas or water, derived in association with oil or gas production and disposed of in a well, if the well used either to facilitate production or for disposal purposes is approved by authority of the state, and if the state determines that such injection or disposal well will not result in the degradation of ground or surface or water resources;

(x) "Wastes" means sewage, industrial waste and all other liquid, gaseous, solid, radioactive, or other substances which may pollute any waters of the state;

(xi) "Waters of the state" means all surface and groundwater, including waters associated with wetlands, within Wyoming;

(xii) "Wetlands" means those areas in Wyoming having all three (3) essential characteristics:

(xiii) "Wetland value" means those socially significant attributes of wetlands such as uniqueness, heritage, recreation, aesthetics and a variety of economic values.

(i) "Acute value" means the one hour average concentration. The EPA has determined that this value, if not exceeded more than once every three years on average, should not result in unacceptable effects on freshwater aquatic organisms and their uses. Acute values represent a response to a stimulus severe enough to induce a rapid reaction, typically in 96 hours or less. Appendix B contains acute values for certain pollutants.

(ii) "Adjacent wetlands" means wetlands that are connected by a defined channel to a surface tributary system, are within the 100 year flood plain of a river or stream, or occupy the fringe of any still water body which is connected by a defined channel to a surface tributary system.

(iii) "Ambient-based criteria" means water quality criteria that are calculated based upon actual ambient or background water body conditions.

(iv) "Aquatic life" means fish, invertebrates, amphibians and other flora and fauna which inhabit waters of the state at some stage of their life cycles. Aquatic life does not include human pathogens or insect pests, aquatic invasive species or other organisms which may be considered "undesirable" by the Wyoming Game and Fish Department or U.S. Fish and Wildlife Service within their appropriate jurisdictions.

(v) "Best management practices (BMPs)" means a practice or combination of practices that after problem assessment, examination of alternative practices, and in some cases public participation, are determined to be the most technologically and economically feasible means of managing, preventing or reducing nonpoint source pollution.

(vi) "Chronic value" means the four day average concentration. The EPA has determined that this value, if not exceeded more than once every three years on average, should not result in unacceptable effects on freshwater aquatic organisms and their uses. Chronic values represent a response to a continuous, long-term stimulus. Appendix B contains chronic values for certain pollutants.

(vii) "Cold water game fish" means burbot (genus Lota), grayling (genus Thymallus), trout, salmon and char (genera Salmo, Oncorhynchus and Salvelinus) and whitefish (genus Prosopium).

(viii) "Construction-related discharge" means discharges of sediment or turbidity related to construction activities in or along waters of the state. Generally, these discharges include, but are not limited to, construction site dewatering, temporary diversions, runoff from construction sites, excavation or equipment operation beneath the water's surface, the discharge of dredged or fill material and placement of structural members such as bridge abutments, culverts, pipelines, etc. into or across any water of the state.

(ix) "Designated uses" means those uses specified in water quality standards for each water body or segment whether or not they are being attained.

(x) "Discharger specific variance" means a time-limited designated use and water quality criteria granted to a specific permittee that reflects the highest attainable condition during the duration of the variance.

(xi) "Dissolved oxygen" means a measure of the amount of free oxygen in water.

(xii) "E. coli" means any of the bacterium in the family Enterobacteriaceae named Escherichia (genus) coli (species).

(xiii) "Effluent dependent water" means a water body with insufficient natural flow to support aquatic life, but which has perennial or intermittent flows for all or a portion of its length as the result of the discharge of wastewater.

(xiv) "Effluent limitations" means any restriction established by the state or by the administrator of the Environmental Protection Agency on quantities, rates and concentrations of chemical, physical, biological and other constituents which are discharged from point sources into waters of the state, including schedules of compliance.

(xv) "Environmental Protection Agency" means the federal Environmental Protection Agency (EPA).

(xvi) "Ephemeral stream" means a stream which flows only in direct response to a single precipitation event in the immediate watershed or in response to a single snow melt event, and which has a channel bottom that is always above the prevailing water table.

(xvii) "Eutrophic" means the condition whereby waters or environments saturated with water become nutrient enriched (especially with phosphorus or nitrogen). This action leads to those waters becoming oxygen depleted or anaerobic.

(xviii) "Existing quality" as used in these regulations refers only to Class 1 waters and means the established chemical, physical and biological water quality as of the date the specific water segment was designated Class 1 with recognition that water quality will fluctuate on a seasonal and year-to-year basis depending upon natural variations in water quantity.

(xix) "Existing use" means those uses actually attained in the water body on or after November 28, 1975, whether or not they are included in the water quality standards.

(xx) "Federal Act" means the Federal Water Pollution Control Act (Clean Water Act) and amendments as of November 27, 2002.

(xxi) "Full body contact water recreation" means any recreational or other surface water use in which there is contact with the water sufficient to pose a significant health hazard (i.e. water skiing, swimming).

(xxii) "Game fish" means bass (genera Micropterus and Ambloplites), catfish and bullheads (genera Ameiurus, Ictalurus and Noturus), crappie (genus Pomoxis), freshwater drum (genus Aplodinotus), grayling (genus Thymallus), burbot (genus Lota), pike (genus Esox), yellow perch (genus Perca), sturgeon (genus Scaphirhynchus), sunfish (genus Lepomis), trout, salmon and char (genera Salmo, Oncorhynchus and Salvelinus), walleye and sauger (genus Sander) and whitefish (genus Prosopium).

(xxiii) "Highest attainable condition" means the designated use and water quality criteria or effluent condition closest to the underlying designated use and water quality criteria or water quality-based effluent limit that is feasible to achieve without causing substantial and widespread economic and social impacts.

(xxiv) "Historic data" means scientifically valid data that are more than five years old or qualitative information that adds some factual information on the historic conditions of a water body. This historic qualitative information may include photographs, journals and factual testimony of persons who have lived near or relied upon the water body, and old records on water use and water conditions.

(xxv) "Hydric soil" means a soil that formed under conditions of saturation, flooding or ponding long enough during the growing season to develop anaerobic conditions in the upper part.

(xxvi) "Hydrophytic vegetation" means a community of plants where, under normal circumstances, more than 50 percent of the composition of the dominant species from all strata are obligate wetland (OBL), facultative wetland (FACW), and/or facultative (FAC) species; or a frequency analysis of all species within the community yields a prevalence index value of less than 3.0 (where OBL = 1.0, FACW = 2.0, FAC = 3.0, FACU (facultative upland) = 4.0, and UPL (upland species) = 5.0).

(xxvii) "Intermittent stream" means a stream or part of a stream where the channel bottom is above the local water table for some part of the year, but is not a perennial stream.

(xxviii) "Isolated water" means any surface water of the state which is not connected by a defined channel to a surface tributary system, is not within the 100 year flood plain of any river or stream and does not occupy the fringe of any still water body which is connected by a defined channel to a surface tributary system.

(xxix) "Main stem" means the major channel of a river or stream as shown on the latest and most detailed records of the Wyoming State Engineer.

(xxx) "Micrograms per liter (µg/L)" means micrograms of solute per liter of solution equivalent to parts per billion (ppb) in liquids, assuming unit density.

(xxxi) "Milligrams per liter (mg/L)" means milligrams of solute per liter of solution equivalent to parts per million (ppm) in liquids, assuming unit density.

(xxxii) "Mixing zone" means limited area or volume of a surface water body within which an effluent becomes thoroughly mixed with the water body.

(xxxiii) "Natural" means that condition which would exist without the measurable influence of man's activities.

(xxxiv) "Natural biotic community" means the population structures which were historically or normally present under a given set of chemical and physical conditions or which would potentially exist without the measurable influence of man's activities had the habitat not been altered.

(xxxv) "Natural water quality" means that quality of water which would exist without the measurable influence of man's activities.

(xxxvi) "Nephelometric turbidity unit (NTU)" means the standard unit used to measure the optical property that causes light to be scattered and absorbed rather than transmitted in straight lines through water, as measured by a nephelometer.

(xxxvii) "Net environmental benefit (NEB)" means a risk management approach to derive site-specific criteria for effluent dependent water bodies that weighs the potential for loss of a permitted effluent discharge against the benefits of augmented flow. A net environmental benefit is demonstrated where there is a credible threat to remove the permitted discharge, the discharge has been shown to create an environmental benefit, removal of the discharge would cause more environmental harm than leaving it in place and the discharge will not pose a health risk to humans, livestock or wildlife.

(xxxviii) "Nongame fish" means all fish species except those listed in Section 2(b)(xxi) above.

(xxxix) "Non-priority pollutant" means any substance or combination of substances other than those listed by EPA under Section 307(a) of the Clean Water Act.

(xl) "Perennial stream" means a stream or part of a stream that flows continually during all of the calendar year as the result of a groundwater discharge or surface runoff.

(xli) "pH" means a term used to express the intensity of acidic or alkaline conditions. pH is a measure of the hydrogen ion activity in a water sample. It is mathematically related to hydrogen ion activity according to the expression: pH = -log 10 (H+), where (H+) is the hydrogen ion activity. A pH value of 7 at 25 degrees Celsius is neutral, with pHs less than 7 progressively more acidic and pHs greater than 7 progressively more basic (alkaline).

(xlii) "PicoCuries per liter (pCi/L)" means a term describing the radiation level of water or solutions. A picocurie is equal to 10-12 curie; a curie is defined as 3.7 x 1010 disintegrations per second.

(xliii) "Pollutant minimization program" means a structured set of activities intended to maintain and/or improve treatment processes and pollutant controls to prevent and reduce pollutant loadings.

(xliv) "Priority pollutants" means those substances or combination of substances that are listed by EPA under Section 307(a) of the Clean Water Act.

(xlv) "Primary contact recreation" means any recreational or other surface water use that could be expected to result in ingestion of the water or immersion (full body contact).

(xlvi) "Salinity" means the total mineral dissolved constituents, after carbonates have been converted to oxides, organics have been oxidized and bromine and iodine have been replaced by chloride. This term is often used interchangeably with the term total dissolved solids.

(xlvii) "Seasonal fishery" means a water body, or portion thereof, which supports game and/or nongame fish or spawning for only a portion of the year, but does not have the natural physical conditions necessary to support those uses on a year round basis. Seasonal fisheries may include intermittent and ephemeral streams, shallow reservoirs, lakes or ponds, which either naturally recruit fish from adjacent perennial water bodies or are managed as put-and-take fisheries.

(xlviii) "Secondary contact recreation" means any recreational or other surface water use in which contact with water is either incidental or accidental and that would not be expected to result in ingestion of the water or immersion.

(xlix) "Storm water", for the purposes of Section 7 of these regulations, means surface runoff from construction sites or industrial activities which are regulated under Section 402(p) of the Clean Water Act and Chapter 2 of the Wyoming Water Quality Rules and Regulations. Excluded from this definition are those storm water discharges associated with industrial activities which are subject to an existing federal effluent limitation guideline addressing storm water and where the constituents listed in the federal effluent limitations have a reasonable potential to affect the receiving waters.

(l) "Surface waters of the state" means all perennial, intermittent and ephemeral defined drainages, lakes, reservoirs and wetlands which are not man-made retention ponds used for the treatment of municipal, agricultural or industrial waste; and all other bodies of surface water, either public or private which are wholly or partially within the boundaries of the state. Nothing in this definition is intended to expand the scope of the Environmental Quality Act, as limited in W.S. 35-11-1104.

(li) "Toxic materials" means those materials or combinations of materials including disease causing agents, which, after discharge and upon exposure, ingestion, inhalation or assimilation into any organism, either directly from the environment or indirectly by ingestion through food chains, will, on the basis of information available to the director of the Wyoming Department of Environmental Quality (department), cause death, disease, behavioral abnormalities, cancer, genetic malfunctions, physiological malfunctions (including malfunctions in reproduction) or physical deformations in such organisms or their offspring.

(lii) "Tributary" means those streams or stream segments which flow into or contribute water to another stream, stream segment, downstream reach of the same stream or other water body.

(liii) "Undesirable aquatic life" means organisms generally associated with degraded or eutrophic conditions. These may include the following organisms where they have replaced members of the natural biotic community: insect pests, aquatic invasive species or other organisms which may be considered "undesirable" by the Wyoming Game and Fish Department or the U.S. Fish and Wildlife Service within their appropriate jurisdictions.

(liv) "Use attainability analysis (UAA)" means a structured scientific assessment of the factors affecting the attainment of the use. The factors may include physical, chemical, biological and economic factors as described in Section 33 of these regulations.

(lv) "Warm water game fish" means bass (genera Micropterus and Ambloplites), catfish and bullheads (genera Ameiurus, Ictalurus and Noturus), crappie (genus Pomoxis), yellow perch (genus Perca), sunfish (genus Lepomis), walleye and sauger (genus Sander), pike (genus Esox), sturgeon (genus Scaphirhynchus) and freshwater drum (genus Aplodinotus).

(lvi) "Wetland hydrology" means the presence of water on or near the land surface at a frequency and duration to cause the formation of hydric soils and support a prevalence of vegetation typically adapted to saturated and/or inundated conditions.

(lvii) "Wyoming Continuing Planning Process (CPP)" means a planning process provided for under Section 303(e)(1) of the Clean Water Act developed through public participation and consisting of policies, procedures and programs that result in the definition and implementation of actions that lead to the prevention, reduction and abatement of water pollution and for the protection and enhancement of water uses in the State of Wyoming. The CPP is continuous in time and is designed to respond to changes in conditions and attitudes. The CPP is adopted by resolution of the Water and Waste Advisory Board and is certified by the Governor.

(lviii) "Wyoming surface waters" shall have the same meaning as "surface waters of the state" defined in Section 2(b) (xlvii).

(lix) "Zone of passage" means a continuous water route which joins segments of a surface water body above and below a mixing zone.

(lx) "404 permit" means a permit issued pursuant to Section 404 of the Clean Water Act to regulate the discharge of dredged or fill materials into surface waters of the United States.