Okla. Admin. Code § 252:740-5-3
Current through Vol. 41, No. 19, June 17, 2024
Section 252:740-5-3 - Reasonable potential(a)General. The need for a permit limit will be determined, on a pollutant-by-pollutant basis, after determination of reasonable potential, which considers assimilation capacity of the receiving water and effluent variability.(b)Use of reasonable potential factor; relationship with wasteload allocation process.(1) The technical report produced by the Oklahoma Water Resources Board entitled "The Incorporation Of Ambient Concentration With That Due To Effluent For Wasteload Allocation" shall be used to determine if there is a reasonable potential for a criterion exceedance outside the mixing zone. C95 = 2.13C mean is used for effluent concentration in the reasonable potential calculation. Cmean is the geometric mean of all effluent concentrations analyzed for the toxicant. If the geometric mean cannot be determined, an arithmetic mean may be substituted. If a large dataset of effluent concentrations is available, the permitting authority may not need to estimate C95; the 95th percentile value can be calculated from the data.(2) The wasteload allocation process is used to determine reasonable potential. C is the reasonable potential concentration on the chronic regulatory mixing zone boundary. C is calculated for chronic criteria in streams as: C = Cb+ (1.94Q*(C95- Cb)) / (1 + Q*) when Q* is less than or equal to 0.1823, or C = Cb+ (C95- Cb) / (6.17 - 15.51Q*) when Q* is greater than 0.1823 and less than 0.3333, or C = C95 when Q* is greater than or equal to 0.3333. Q* = Q e /Qu. Q* is the dilution capacity. C is calculated for lakes as: pipe: C = Cb+ (D(C95- Cb)) / 20.15 when D is greater than or equal to 3 feet, or canal: C = Cb+ (W1/2(C95- Cb)) / 4.2 when W is greater than or equal to 3 feet. D is the diameter of the discharge pipe in feet and W is the width of the canal in feet. D and W shall not be less than three feet for implementation purposes. When C is the concentration on the acute regulatory mixing zone boundary it is calculated as C = Cb+ (Qe(C95- Cb) / 100). If Qe is greater than 100 cfs, then 100 cfs shall be substituted for Qe.(3) For regulatory purposes, there is a reasonable potential for chronic toxicity if concentrations of ammonia outside the chronic regulatory mixing zone exceed 6 mg/L.Okla. Admin. Code § 252:740-5-3
Adopted by Oklahoma Register, Volume 40, Issue 6, December 1, 2022, eff. 10/25/2022Adopted by Oklahoma Register, Volume 40, Issue 24, September 1, 2023, eff. 9/15/2023