Okla. Admin. Code § 252:740-7-2

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

Section 252:740-7-2 - Determination and use of regulatory flow

(a)General. OAC 252:730-5-10(1), OAC 252:730-5-10(6)(B), and OAC 252:730-5-20(b) require that long-term average receiving stream flows shall be used to implement water column numerical criteria to protect human health.

(b)Long-term average flow on gaged receiving streams. Mean annual average flow as determined in the technical report produced by the Oklahoma Water Resources Board entitled "Estimation of Mean Annual Average Flows" shall be used for long-term average flow in receiving streams which are or have been measured by USGS gages.

(c)Mean annual average flows on ungaged receiving streams. Mean annual average flow may be estimated on streams where flow is not routinely measured. This method for estimation is demonstrated in the technical report produced by the Oklahoma Water Resources Board entitled "Estimation Of Mean Annual Average Flows". Other scientifically defensible methods of long-term average flow estimation are permissible if approved by the permitting authority.

(d)Long-term average flow in lakes. Q_u cannot be estimated in a lake as easily as it can be for a stream. Therefore, mean annual average discharge from the lake shall be used for Q_u.

(e)Long-term effluent flow. The regulatory effluent flow, Q_e, is long-term average effluent flow over the previous two years for industrial discharges if the permitting authority determines that sufficient data are available. For other discharges, Q_e is the design flow.

Okla. Admin. Code § 252:740-7-2

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