Washington Administrative Code › Title 173 - Ecology, Department of (See also Titles 197, 317, 372, and 508) › Chapter 173-201A - Water quality standards for surface waters of the state of Washington › Part I - INTRODUCTION › Section 173-201A-020 - Definitions

Current through Register Vol. 24-14, July 15, 2024
The following definitions are intended to facilitate the use
				  of chapter 173-201A WAC:
"1-DMax"
or
"1-day maximum
				  temperature"
is the highest water temperature reached on any given day.
				  This measure can be obtained using calibrated maximum/minimum thermometers or
				  continuous monitoring probes having sampling intervals of 30 minutes or
				  less.
"7-DADMax"
or
"7-day average of the daily
				  maximum temperatures"
is the arithmetic average of seven consecutive
				  measures of daily maximum temperatures. The 7-DADMax for any individual day is
				  calculated by averaging that day's daily maximum temperature with the daily
				  maximum temperatures of the three days prior and the three days after that
				  date.
"Action value"
means a total phosphorus (TP)
				  value established at the upper limit of the trophic states in each ecoregion
				  (see Table 230(1)). Exceedance of an action value indicates that a problem is
				  suspected. A lake-specific study may be needed to confirm if a nutrient problem
				  exists.
"Actions"
refers broadly to any human projects
				  or activities.
"Acute conditions"
are changes in the physical,
				  chemical, or biologic environment which are expected or demonstrated to result
				  in injury or death to an organism as a result of short-term exposure to the
				  substance or detrimental environmental condition.
"AKART"
is an acronym for "all known, available,
				  and reasonable methods of prevention, control, and treatment." AKART shall
				  represent the most current methodology that can be reasonably required for
				  preventing, controlling, or abating the pollutants associated with a discharge.
				  The concept of AKART applies to both point and nonpoint sources of pollution.
				  The term "best management practices," typically applied to nonpoint source
				  pollution controls is considered a subset of the AKART requirement.
"Ambient water quality"
refers to the conditions
				  and properties of a surface water of the state as determined by the results of
				  water samples, measurements, or observations.
"Background"
means the biological, chemical, and
				  physical conditions of a water body, outside the area of influence of the
				  discharge under consideration. Background sampling locations in an enforcement
				  action would be up-gradient or outside the area of influence of the discharge.
				  If several discharges to any water body exist, and enforcement action is being
				  taken for possible violations to the standards, background sampling would be
				  undertaken immediately up-gradient from each discharge.
"Best management practices (BMP) "
means
				  physical, structural, and/or managerial practices approved by the department
				  that, when used singularly or in combination, prevent or reduce pollutant
				  discharges.
"Biological assessment"
is an evaluation of the
				  biological condition of a water body using surveys of aquatic community
				  structure and function and other direct measurements of resident biota in
				  surface waters.
"Bog"
means those wetlands that are acidic, peat
				  forming, and whose primary water source is precipitation, with little, if any,
				  outflow.
"Carcinogen"
means any substance or agent that
				  produces or tends to produce cancer in humans. For implementation of this
				  chapter, the term carcinogen will apply to substances on the United States
				  Environmental Protection Agency lists of A (known human) and B (probable human)
				  carcinogens, and any substance which causes a significant increased incidence
				  of benign or malignant tumors in a single, well conducted animal bioassay,
				  consistent with the weight of evidence approach specified in the United States
				  Environmental Protection Agency's Guidelines for Carcinogenic Risk Assessment
				  as set forth in 51 FR 33992 et seq. as presently published or as subsequently
				  amended or re-published.
"Chronic conditions"
are changes in the
				  physical, chemical, or biologic environment which are expected or demonstrated
				  to result in injury or death to an organism as a result of repeated or constant
				  exposure over an extended period of time to a substance or detrimental
				  environmental condition.
"Combined sewer overflow (CSO) treatment plant"
is a facility that provides at-site treatment as provided for in chapter
				  173-245 WAC. A CSO treatment plant is a specific facility identified in a
				  department-approved CSO reduction plan (long-term control plan) that is
				  designed, operated and controlled by a municipal utility to capture and treat
				  excess combined sanitary sewage and stormwater from a combined sewer
				  system.
"Compliance schedule"
or
"schedule of
				  compliance"
is a schedule of remedial measures included in a permit or
				  an order, including an enforceable sequence of interim requirements (for
				  example, actions, operations, or milestone events) leading to compliance with
				  an effluent limit, other prohibition, or standard.
"Created wetlands"
means those wetlands
				  intentionally created from nonwetland sites to produce or replace natural
				  wetland habitat.
"Critical condition"
is when the physical,
				  chemical, and biological characteristics of the receiving water environment
				  interact with the effluent to produce the greatest potential adverse impact on
				  aquatic biota and existing or designated water uses. For steady-state
				  discharges to riverine systems the critical condition may be assumed to be
				  equal to the 7Q10 flow event unless determined otherwise by the
				  department.
"Damage to the ecosystem"
means any demonstrated
				  or predicted stress to aquatic or terrestrial organisms or communities of
				  organisms which the department reasonably concludes may interfere in the health
				  or survival success or natural structure of such populations. This stress may
				  be due to, but is not limited to, alteration in habitat or changes in water
				  temperature, chemistry, or turbidity, and shall consider the potential build up
				  of discharge constituents or temporal increases in habitat alteration which may
				  create such stress in the long term.
"Department"
means the state of Washington
				  department of ecology.
"Designated uses"
are those uses specified in
				  this chapter for each water body or segment, regardless of whether or not the
				  uses are currently attained.
"Director"
means the director of the state of
				  Washington department of ecology.
"Drainage ditch"
means that portion of a
				  designed and constructed conveyance system that serves the purpose of
				  transporting surplus water; this may include natural water courses or channels
				  incorporated in the system design, but does not include the area adjacent to
				  the water course or channel.
"Ecoregions"
are defined using EPAs
Ecoregions of the Pacific Northwest
Document No. 600/3-86/033
				  July 1986 by Omernik and Gallant.
"Enterococci"
refers to a subgroup of fecal
				  streptococci that includes
S. faecalis, S. faecium, S.
				  gallinarum,
and
S. avium
. The enterococci are
				  differentiated from other streptococci by their ability to grow in 6.5% sodium
				  chloride, at pH 9.6, and at 10°C and 45°C.
"
E. coli
"
is a bacterium in the
				  family Enterobacteriaceae named Escherichia coli and is a common inhabitant of
				  the intestinal tract of warm-blooded animals, and its presence in water samples
				  is an indication of fecal pollution and the possible presence of enteric
				  pathogens.
"Existing uses"
means those uses actually
				  attained in fresh or marine waters on or after November 28, 1975, whether or
				  not they are designated uses. Introduced species that are not native to
				  Washington, and put-and-take fisheries comprised of nonself-replicating
				  introduced native species, do not need to receive full support as an existing
				  use.
"Fecal coliform"
means that portion of the
				  coliform group which is present in the intestinal tracts and feces of
				  warm-blooded animals as detected by the product of acid or gas from lactose in
				  a suitable culture medium within 24 hours at 44.5 plus or minus 0.2 degrees
				  Celsius.
"Geometric mean"
means either the nth root of a
				  product of n factors, or the antilogarithm of the arithmetic mean of the
				  logarithms of the individual sample values.
"Ground water exchange"
means the discharge and
				  recharge of ground water to a surface water. Discharge is inflow from an
				  aquifer, seeps or springs that increases the available supply of surface water.
				  Recharge is outflow downgradient to an aquifer or downstream to surface water
				  for base flow maintenance. Exchange may include ground water discharge in one
				  season followed by recharge later in the year.
"Hardness"
means a measure of the calcium and
				  magnesium salts present in water. For purposes of this chapter, hardness is
				  measured in milligrams per liter and expressed as calcium carbonate
				  (CaCO3).
"Intake credit"
is a procedure for establishing
				  effluent limits that takes into account the amount of a pollutant that is
				  present in waters of the state, at the time water is removed from the same body
				  of water by the discharger or other facility supplying the discharger with
				  intake water.
"Intragravel dissolved oxygen"
means the
				  concentration of dissolved oxygen in the spaces between sediment particles in a
				  streambed.
"Irrigation ditch"
means that portion of a
				  designed and constructed conveyance system that serves the purpose of
				  transporting irrigation water from its supply source to its place of use; this
				  may include natural water courses or channels incorporated in the system
				  design, but does not include the area adjacent to the water course or
				  channel.
"Lakes"
shall be distinguished from riverine
				  systems as being water bodies, including reservoirs, with a mean detention time
				  of greater than 15 days.
"Lake-specific study"
means a study intended to
				  quantify existing nutrient concentrations, determine existing characteristic
				  uses for lake class waters, and potential lake uses. The study determines how
				  to protect these uses and if any uses are lost or impaired because of
				  nutrients, algae, or aquatic plants. An appropriate study must recommend a
				  criterion for total phosphorus (TP), total nitrogen (TN) in µg/l, or
				  other nutrient that impairs characteristic uses by causing excessive algae
				  blooms or aquatic plant growth.
"Mean detention time"
means the time obtained by
				  dividing a reservoir's mean annual minimum total storage by the 30-day 10-year
				  low-flow from the reservoir.
"Migration"
or
"translocation"
means any natural movement of an organism or community of organisms from one
				  locality to another locality.
"Migration for naturally limited waters"
is a
				  subcategory of the aquatic life use of salmonid rearing and migration that is
				  limited by the natural physical, chemical, or biological characteristics of the
				  water body.
"Mixing zone"
means that portion of a water body
				  adjacent to an effluent outfall where mixing results in the dilution of the
				  effluent with the receiving water. Water quality criteria may be exceeded in a
				  mixing zone as conditioned and provided for in WAC
				  173-201A-400.
"Natural conditions"
or
"natural
				  background levels"
means surface water quality that was present before
				  any human-caused pollution. When estimating natural conditions in the
				  headwaters of a disturbed watershed it may be necessary to use the less
				  disturbed conditions of a neighboring or similar watershed as a reference
				  condition. (See also WAC
				  173-201A-260(1).)
"New or expanded actions"
mean human actions
				  that occur or are regulated for the first time, or human actions expanded such
				  that they result in an increase in pollution, after July 1, 2003, for the
				  purpose of applying this chapter only.
"Nonpoint source"
means pollution that enters
				  any waters of the state from any dispersed land-based or water-based activities
				  including, but not limited to, atmospheric deposition; surface water runoff
				  from agricultural lands, urban areas, or forest lands; subsurface or
				  underground sources; or discharges from boats or marine vessels not otherwise
				  regulated under the National Pollutant Discharge Elimination System
				  program.
"Outstanding resource waters"
are high quality
				  waters designated by the state due to their exceptional water quality,
				  ecological or recreational significance, unique habitat, or cold water refuge.
				  Outstanding resource waters are given the highest level of protection under the
				  state antidegradation policy.
"Permit"
means a document issued pursuant to
				  chapter 90.48 RCW specifying the waste treatment and control requirements and
				  waste discharge conditions.
"pH"
means the negative logarithm of the
				  hydrogen ion concentration.
"Pollution"
means such 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 such discharge of any liquid, gaseous, solid, radioactive, or
				  other substance into any waters of the state as will or is likely to create a
				  nuisance or render such waters harmful, detrimental, or injurious to the public
				  health, safety, or welfare, or to domestic, commercial, industrial,
				  agricultural, recreational, or other legitimate beneficial uses, or to
				  livestock, wild animals, birds, fish, or other aquatic life.
"Primary contact recreation"
means activities
				  where a person would have direct contact with water to the point of complete
				  submergence including, but not limited to, skin diving, swimming, and water
				  skiing.
"Salmonid spawning, rearing, and migration for
				  naturally limited waters"
is a subcategory of the aquatic life use of
				  salmonid spawning, rearing, and migration that is limited by the natural
				  physical, chemical, or biological characteristics of the water body.
"Shoreline stabilization"
means the anchoring of
				  soil at the water's edge, or in shallow water, by fibrous plant root complexes;
				  this may include long-term accretion of sediment or peat, along with shoreline
				  progradation in such areas.
"Spatial median"
is the middle value of multiple
				  ranked measurements taken within the sampling area.
"Stormwater"
means that portion of precipitation
				  that does not naturally percolate into the ground or evaporate, but flows via
				  overland flow, interflow, pipes, and other features of a stormwater drainage
				  system into a defined surface water body, or a constructed infiltration
				  facility.
"Stormwater attenuation"
means the process by
				  which peak flows from precipitation are reduced and runoff velocities are
				  slowed as a result of passing through a surface water body.
"Surface waters of the state"
includes lakes,
				  rivers, ponds, streams, inland waters, saltwaters, wetlands and all other
				  surface waters and water courses within the jurisdiction of the state of
				  Washington.
"Temperature"
means water temperature expressed
				  in degrees Celsius (°C).
"Treatment wetlands"
means those wetlands
				  intentionally constructed on nonwetland sites and managed for the primary
				  purpose of waste-water or stormwater treatment. Treatment wetlands are
				  considered part of a collection and treatment system, and generally are not
				  subject to the criteria of this chapter.
"Trophic state"
means a classification of the
				  productivity of a lake ecosystem. Lake productivity depends on the amount of
				  biologically available nutrients in water and sediments and may be based on
				  total phosphorus (TP). Secchi depth and chlorophyll-a measurements may be used
				  to improve the trophic state classification of a lake. Trophic states used in
				  this rule include, from least to most nutrient rich, ultra-oligotrophic,
				  oligotrophic, lower mesotrophic, upper mesotrophic, and eutrophic.
"Turbidity"
means the clarity of water expressed
				  as nephelometric turbidity units (NTU) and measured with a calibrated
				  turbidimeter.
"Upwelling"
means the natural process along
				  Washington's Pacific Coast where the summer prevailing northerly winds produce
				  a seaward transport of surface water. Cold, deeper more saline waters rich in
				  nutrients and low in dissolved oxygen, rise to replace the surface water. The
				  cold oxygen deficient water enters Puget Sound and other coastal estuaries at
				  depth where it displaces the existing deep water and eventually rises to
				  replace the surface water. Such surface water replacement results in an overall
				  increase in salinity and nutrients accompanied by a depression in dissolved
				  oxygen. Localized upwelling of the deeper water of Puget Sound can occur
				  year-round under influence of tidal currents, winds, and geomorphic
				  features.
"USEPA"
means the United States Environmental
				  Protection Agency.
"Variance"
is a time-limited designated use and
				  criterion as defined in 40
				  C.F.R. 131.3, and must be adopted by
				  rule.
"Wetlands"
means areas that are inundated or
				  saturated by surface water or ground water at a frequency and duration
				  sufficient to support, and that under normal circumstances do support, a
				  prevalence of vegetation typically adapted for life in saturated soil
				  conditions. Wetlands generally include swamps, marshes, bogs, and similar
				  areas. Wetlands do not include those artificial wetlands intentionally created
				  from nonwetland sites including, but not limited to, irrigation and drainage
				  ditches, grass-lined swales, canals, detention facilities, wastewater treatment
				  facilities, farm ponds, and landscape amenities, or those wetlands created
				  after July 1, 1990, that were unintentionally created as a result of the
				  construction of a road, street, or highway. Wetlands may include those
				  artificial wetlands intentionally created from nonwetland areas to mitigate the
				  conversion of wetlands. (Water bodies not included in the definition of
				  wetlands as well as those mentioned in the definition are still waters of the
				  state.)
"Wildlife habitat"
means waters of the state
				  used by, or that directly or indirectly provide food support to, fish, other
				  aquatic life, and wildlife for any life history stage or activity.
Statutory Authority:
					 RCW
					    90.48.035. 11-09-090 (Order 10-10), §
					 173-201A-020, filed 4/20/11, effective 5/21/11. Statutory Authority:
					 Chapters
					 90.48 and
					 90.54 RCW. 03-14-129 (Order 02-14),
					 § 173-201A-020, filed 7/1/03, effective 8/1/03. Statutory Authority:
					 Chapter
					 90.48 RCW and  40 C.F.R.
					 131 . 97-23-064 (Order 94-19), § 173-201A-020, filed 11/18/97, effective
					 12/19/97. Statutory Authority:
					 Chapter
					 90.48 RCW. 92-24-037
					 (Order 92-29), § 173-201A-020, filed 11/25/92, effective
					 12/26/92.