Okla. Admin. Code § 252:740-9-3
Current through Vol. 41, No. 19, June 17, 2024
Section 252:740-9-3 - Regulatory flows(a)General. Six regulatory flows are required for implementation of yearly mean standards and sample standards. They include stream flows, regulatory flows for lakes and regulatory effluent flows.(b)Long-term average flows for streams. The greater of 1.47 cfs or mean annual average flow, A, will be used by the permitting authority for long-term average flows to implement yearly mean standards. Mean annual average flows may be obtained from the USGS publication entitled "Statistical Summaries of Streamflow in and near Oklahoma Through 2007". They may also be estimated on streams without gages using the Oklahoma Water Resources Board publication entitled "Estimation of Mean Annual Average Flows" (OWRB Technical Report 96-2).(c)Long-term average flow for lakes. Mean annual average discharge from the lake, A, shall be used to implement the Agriculture beneficial use.(d)Regulatory long-term effluent flows. If the permitting authority determines that sufficient data is available to calculate the mean annual effluent discharge, then such discharge shall be the long-term effluent flow, Qel. If the permitting authority determines insufficient data is available to calculate the mean annual effluent discharge, then the design flow shall be the long-term effluent flow, Qel.(e)Short-term average flow for streams. OAC 252:730-5-4(d) requires that short-term average flow, Qs, be used to implement sample standards. The short-term average flow is determined so that short-term and long-term wasteload allocations are equally likely to be more stringent, depending on the historical concentration distribution for a particular segment. Qs shall equal the greater of 1.0 cfs or 0.68 A, where A is mean annual average stream flow.(f)Short-term average flows for lakes. Short-term average flows for lakes are also determined by the formula in OAC 242:740-9-3(e). In this case A is the mean annual average lake discharge.(g)Short-term average effluent flows. If the permitting authority determines that sufficient data is available to calculate the highest monthly average discharge for industrial discharges, then such discharge shall be the short-term average effluent flow, Qes. If the permitting authority determines insufficient data is available to calculate the highest monthly average discharge for industrial discharges, then the design flow shall be the short-term average effluent flow, Q es.Okla. Admin. Code § 252:740-9-3
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