Oklahoma Administrative Code › Title 252 - Department of Environmental Quality › Chapter 740 - Implementation of Oklahoma's Water Quality Standards › Subchapter 1 - General Provisions › Section 252:740-1-2 - Definitions

Current through Vol. 41, No. 20, July 1, 2024
In addition to definitions of terms found in OAC
				  252:730-1-2, 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 the Environmental Quality Board.
"BOD"
means biochemical oxygen demand.
"C"
means maximum concentration on the mixing
				  zone boundary.
"C95"
means the 95th
				  percentile maximum likelihood concentration.
"Cb"
means background
				  concentration.
"Ce"
means effluent
				  concentration.
"cfs"
means cubic feet per second.
"Cmean"
means the
				  geometric mean of all effluent concentrations analyzed for the toxicant.
"Ct"
means the
				  appropriate criterion listed in OAC 252:730.
"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.
"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 252:730-3-2(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 252:730.
"LC50"
means the lethal concentration as defined
				  in OAC 252:730-1-2.
"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
				  252:730-1-2.
"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
				  252:730-3-2(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.
"Qe"
means the regulatory
				  effluent flow.
"Qel"
means long-term
				  average effluent flow.
"Qes"
means short-term
				  average effluent flow.
"Qu"
means the regulatory
				  receiving stream flow.
"Regulatory mixing zone"
means the volume of
				  receiving water described in OAC
				  252:730-5-26.
"Reasonable potential factor"
means the 95th
				  percentile maximum likelihood estimator for a lognormal distribution.
"SS"
means sample standard as defined in OAC
				  252:730-1-2.
"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.
"Tc"
means the
				  temperature criterion.
"Tf"
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 252:730-1-2.