Okla. Admin. Code § 252:740-1-2
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.
Okla. Admin. Code § 252:740-1-2