Oklahoma Administrative Code › Title 785 - Oklahoma Water Resources Board › Chapter 46 - Implementation of Oklahoma's Water Quality Standards › Subchapter 1 - General Provisions › Section 785:46-1-2 - Definitions

Current through Vol. 41, No. 20, July 1, 2024
In addition to definitions of terms found in OAC
											  785:45-1-2, which are incorporated herein by
											  reference, the following words, terms and notations, when used in this Chapter, shall have the following
											  meanings unless the context clearly indicates otherwise:
"7T2"
means the seven-day maximum temperature likely to
											  occur with a 50% probability each year. The 7T2 is calculated using a moving average of seven consecutive
											  days for each year in a given record. These seven day receiving stream temperature values are ranked in
											  descending order. An order number, m, is calculated based on the number of years of record, n, with a
											  recurrence interval of 2 years, as m = (n+1)/2. The m 
											  th  highest average temperature is the
											  7T2.
"A"
means mean annual average flow.
"ACR"
means acute to chronic ratio.
"Acute to chronic ratio"
means LC50/NOEC. The NOEC is the
											  highest concentration at which no effect on test organisms is observed over a relatively long period.
											  Quarterly biomonitoring over the life of the permit is sufficient to determine the ACR if the NOEC and LC50
											  may be determined. If the ACR is unknown, a default value of 10 may be used for implementation
											  purposes.
"Background"
means the ambient condition upstream or
											  upgradient from a facility, practice or activity which has not been affected by that facility, practice or
											  activity.
"Beneficial use limitation"
means a more stringent
											  restriction than that required to protect the beneficial use. A prohibition on new point sources is an
											  example of a beneficial use limitation.
"Board"
means Oklahoma Water Resources Board.
"BOD"
means biochemical oxygen demand.
"C"
means maximum concentration on the mixing zone
											  boundary.
"C 95"
means the 95th percentile
											  maximum likelihood concentration.
"Cb"
means background
											  concentration.
"Ce"
means effluent
											  concentration.
"cfs"
means cubic feet per second.
"C mean"
means the geometric mean of
											  all effluent concentrations analyzed for the toxicant.
"Ct"
means the appropriate criterion
											  listed in OAC 785:45.
"CBOD"
means carbonaceous biochemical oxygen demand.
"Coefficient of variation"
means standard deviation divided
											  by the mean.
"Continuing Planning Process (CPP)"
means the most recent
											  edition of the document produced annually by the Oklahoma Department of Environmental Quality which describes
											  water quality programs implemented within the State.
"Continuing toxicity"
means a tendency to be toxic.
"Control"
means test organisms exposed to 0% effluent as
											  part of the whole effluent toxicity testing procedure.
"Cooling water reservoir"
means a privately owned reservoir
											  used in the process of cooling water for industrial purposes.
"CPP"
means the Continuing Planning Process document.
"CV"
means coefficient of variation.
"D"
means diameter of the discharge pipe in feet.
"df"
means dilution factor.
"Dilution capacity"
means a measure of the ability of the
											  receiving stream to dilute effluent, defined as the ratio of the regulatory effluent flow to the regulatory
											  receiving stream flow.
"Dilution factor"
means a measure of the minimum dilution
											  that occurs on the mixing zone boundary.
"Discharge to a lake"
means a discharge within the lake's
											  normal pool elevation as listed in the Oklahoma Water Atlas, Oklahoma Water Resources Board Publication 135,
											  May 1990, excluding discharges to lock and dam reservoirs.
"Discharge to a stream"
means (1) any discharge outside the
											  normal pool elevation of a lake as such elevation is listed in the Oklahoma Water Atlas, Oklahoma Water
											  Resources Board Publication 135, May 1990, and (2) any discharge to a lock and dam reservoir, such as Webbers
											  Falls Reservoir and Robert S. Kerr Reservoir.
"DO"
means dissolved oxygen.
"Drainage area"
means the area above the discharge drained
											  by the receiving stream.
"Event mean concentration"
means the flow-weighted average
											  for a given storm event. The flow-weighted average is represented as the sum of the loads calculated for a
											  series of storm samples divided by the sum of the discharges calculated for each of the storm samples.
"EPA"
means the United States Environmental Protection
											  Agency.
"HQW"
means high quality waters as defined in OAC
											  785:45-3-2(b).
"Implementation Plan"
means a Water Quality Standards
											  Implementation Plan developed and promulgated by a state environmental agency as required by 27A O.S. §
											  1-1-202.
"Increased load"
means the mass of pollutant discharged
											  which is greater than the permitted mass loadings and concentrations, as appropriate, in the discharge permit
											  effective when the SWS, SWS-R,HQW, or ORW beneficial use limitation was assigned.
"Lake mixing zone"
means a volume extending one hundred feet
											  from the source for implementation purposes, unless otherwise specified in OAC 785:45.
"LC50"
means the lethal concentration as defined in OAC
											  785:45-1-2.
"LMFO"
means licensed managed feeding operation as defined
											  in 2 O.S. 9-202.
"Mean annual average flow"
means the annual mean flow found
											  in "Statistical Summaries", USGS publication no. 87-4205, or most recent version thereof, or other annual
											  mean flow as approved by the Oklahoma Water Resources Board or the permitting authority.
"Monthly average level"
means the concentration of a
											  toxicant in the permit which may not be exceeded by the observed effluent concentration averaged over a
											  calendar month.
"Naturally occurring condition"
means any condition
											  affecting water quality which is not caused by human influence, including, but not limited to, soils,
											  geology, hydrology, climate, wildlife, and water flow with specific consideration given to seasonal and other
											  natural variations.
"NLW"
means nutrient-limited watershed as defined in OAC
											  785:45-1-2.
"NOEC"
means no observed effect concentration.
"NPDES"
means National Pollutant Discharge Elimination
											  System.
"Normal pool elevation"
means the elevations listed in the
											  "Oklahoma Water Atlas", Oklahoma Water Resources Board publication no. 135, or most recent version
											  thereof.
"ORW"
means Outstanding Resource Waters as defined in OAC
											  785:45-3-2(a).
"Outfall"
means a point source which contains all the
											  effluent being discharged to the receiving water.
"OWQS"
means Oklahoma Water Quality Standards.
"Permitting authority"
means state environmental agency as
											  defined or provided in Title 27A of the Oklahoma Statutes having jurisdiction as provided by law.
"Persistent toxicity"
means toxicity due to effluent
											  constituents which are not subject to decay, degradation, transformation, volatilization, hydrolysis, or
											  photolysis.
"Q*"
means dilution capacity.
"Q e"
means the regulatory effluent
											  flow.
"Q el"
means long term average
											  effluent flow.
"Q es"
means short term average
											  effluent flow.
"Q u"
means the regulatory receiving
											  stream flow.
"Regulatory mixing zone"
means the volume of receiving water
											  described in
											  785:45-5-26.
"Reasonable potential factor"
means the 95th percentile
											  maximum likelihood estimator for a lognormal distribution.
"SS"
means sample standard as defined in OAC
											  785:45-1-2.
"Storm event
" means precipitation, after a minimum of 72
											  hours has elapsed since cessation of previous precipitation, in the watershed of a stream segment that
											  produces a 30 percent rise in stream flow over the average flow of the preceding 72 hours resulting from
											  surface run-off.
"SWS"
means Sensitive Public and Private Water
											  Supplies.
"SWS-R"
means waterbodies classified as sensitive public and
											  private water supplies that may be augmented with reclaimed municipal water for the purpose of indirect
											  potable reuse.
"T'"
means maximum temperature difference at the edge of the
											  mixing zone boundary.
"Ta "
means regulatory ambient
											  temperature.
"T c"
means the temperature
											  criterion.
"T f"
means the 95th percentile
											  maximum observed effluent temperature.
"TDS"
means total dissolved solids at 180C.
"TMDL"
means total maximum daily load.
"Total maximum daily load"
means the sum of individual
											  wasteload allocations for point sources, safety reserves, and loads from nonpoint source and natural
											  backgrounds.
"Trophic State Index"
means a numerical quantification of
											  lake productivity. The Trophic State Index shall be determined by TSI = 9.81 x Ln(chlorophyll-a) +
											  30.6.
"TSI"
means Trophic State Index.
"TSS"
means total suspended solids.
"USGS"
means United States Geological Survey.
"W"
means canal width in feet.
"YMS"
means yearly mean standard as defined in OAC
											  785:45-1-2.
Added at 13 Ok Reg 2891, eff 7-1-96;
											  Amended at 15 Ok Reg 2873, eff 7-1-98; Amended at 16 Ok Reg 3251, eff 7-12-99; Amended at 17 Ok Reg 1775, eff
											  7-1-00; Amended at 19 Ok Reg 2512, eff 6-27-02; Amended at 20 Ok Reg 1429, eff 7-1-03; Amended at 21 Ok Reg
											  1910, eff 7-1-04; Amended at 22 Ok Reg 1607, eff 7-1-05; Amended at 23 Ok Reg 1568, eff 7-1-06; Amended at 24
											  Ok Reg 2445, eff 7-1-07; Amended at 25 Ok Reg 1455, eff 7-1-08