Okla. Admin. Code § 252:740-9-4

Current through Vol. 41, No. 19, June 17, 2024

Section 252:740-9-4 - Reasonable potential

(a)General. The need for a permit limit will be determined on a mineral constituent basis, after application of the reasonable potential equation specified in (b) of this Section, which considers assimilation capacity of the receiving water and effluent variability.

(b)Reasonable potential equation. OAC 252:730-5-13(d) requires that complete mixing of effluent and receiving water be taken into account in the reasonable potential equation. The use of mass balance to obtain wasteload allocations for complete mixing is codified at OAC 252:740-7-3(a). Therefore, the reasonable potential equation for mineral constituents is C = (Q_u BC + Q _e C₉₅) /Q _u + Q_e), where C ₉₅ = 2.13 C_mean, where C _mean is the geometric mean of all effluent concentrations analyzed for the mineral. If the geometric mean cannot be determined, an arithmetic mean may be used. If sufficient effluent concentration observations exist as determined by the permitting authority, then the permitting authority may compute the 95th percentile concentration and use it as C₉₅in accordance with OAC 252:740-5-3(b)(1).

(c)Reasonable potential to exceed yearly mean standard. Q _u = A and Q_e = Q _el in OAC 252:740-9-4(b) to obtain a long-term average concentration in-stream after complete mixing. If C is greater than the higher of the YMS or 700 milligrams per liter for TDS or 200 milligrams per liter for chlorides and sulfates, there is a reasonable potential to exceed an Agriculture beneficial use criterion, and a permit limit is required.

(d)Reasonable potential to exceed sample standard. Q_u =0.68A and Q _e = Q_es in OAC 252:740-9-4(b) to obtain a short-term average concentration in-stream after complete mixing. If C is greater than the higher of the SS or 700 milligrams per liter for TDS or 200 milligrams per liter for chlorides and sulfates, there is a reasonable potential to exceed an Agriculture beneficial use criterion, so a permit limit is required.

Okla. Admin. Code § 252:740-9-4

Adopted by Oklahoma Register, Volume 40, Issue 6, December 1, 2022, eff. 10/25/2022

Adopted by Oklahoma Register, Volume 40, Issue 24, September 1, 2023, eff. 9/15/2023