Okla. Admin. Code § 785:46-15-14

Current through Vol. 42, No. 4, November 1, 2024

Section 785:46-15-14 - Assessment of Aesthetics Support

(a)General provisions for all waterbodies other than Scenic Rivers. The tests prescribed in OAC 785:46-15-4 may be used to determine whether the beneficial use of Aesthetics designated in OAC 785:45 for a waterbody other than the Scenic Rivers is supported.

(b)Special provisions for Scenic River reaches of Mountain Fork River, Lee Creek and Little Lee Creek.

(1)Scope and applicability. This subsection shall be used to determine whether the Aesthetics beneficial use designated in OAC 785:45 is supported with respect to thetotal phosphorus criterionfor Mountain Fork River, Lee Creek and Little Lee Creek.

(2)Data and procedure.

(A) The data used shall satisfy all of the requirements of 785:46-15-3 except subsection (f) thereof. Notwithstanding such requirements, the data shall include samples collected from stream flow of at least six (6) storm events per calendar year or, if fewer than nine (9) storm events occurred in that year, then the majority of the storm events that occurred that year.

(B) Whenever multiple samples are taken from a single storm event, the event mean concentration shall be determined and used as representative of that storm event.

(C) A three-calendar-month geometric mean concentration shall be determined each month using the total phosphorus data from that month together with such data from the preceding two calendar months.

(3)Support tests.

(A) The Aesthetics beneficial use designated for a segment of a Scenic River shall be deemed to be supported with respect to total phosphorus if less than 25% of the monthly determinations made in accordance with (b)(2)(C) of this Section exceed 0.037 mg/L total phosphorus.

(B) The Aesthetics beneficial use designated for a segment of a Scenic River shall be deemed to be not supported with respect to total phosphorus if 25% or greater of the monthly determinations made in accordance with (b)(2)(C) of this Section exceed 0.037 mg/L total phosphorus.

(c)Special provisions for Scenic River reaches of Illinois River, Flint Creek, and Barren Fork Creek.

(1)Scope and applicability. This subsection shall be used to determine whether the Aesthetics beneficial use designated in OAC 785:45 is supported with respect to the total phosphorus criterion for Illinois River, Flint Creek, and Barren Fork Creek.

(2)Data and procedure.

(A) The data used must satisfy all the requirements of 785:46-15-3, unless otherwise specified in this subsection.

(B) A rolling 6-month arithmetic mean must be calculated based on data from the current month and the five (5) preceding months. The calculation of a rolling 6-month arithmetic mean must include at least four values from four separate months. All available individual data values from any given month must be included in the rolling 6-month arithmetic mean calculation.

(C) A minimum of ten (10) rolling 6-month arithmetic means are required to assess the Aesthetic beneficial use within a one-year period. The minimum of ten (10) rolling 6-month arithmetic means shall not be required upon affirmation that the beneficial use is not supported per of 785:46-5-14(c)(3)(B).

(D) A minimum of thirty (30) rolling 6-month arithmetic means are required to assess the Aesthetic beneficial use within a five-year period. The minimum of thirty (30) rolling 6-month arithmetic means shall not be required upon affirmation that the beneficial use is not supported per of 785:46-5-14(c)(3)(B).

(3)Support Tests.

(A) If no more than one rolling 6-month arithmetic mean in any one-year period and not more than three rolling 6-month arithmetic means in any 5-year period exceed the total phosphorus criterion magnitude of 0.037 mg/L, the Aesthetic beneficial use is supported.

(B) If more than one rolling 6-month arithmetic mean in any one-year period or more than three rolling 6-month arithmetic means in any 5-year period exceed the total phosphorus criterion magnitude of 0.037 mg/L, the Aesthetic beneficial use is not supported.

Okla. Admin. Code § 785:46-15-14

Added at 25 Ok Reg 1455, eff 7-1-08

Amended by Oklahoma Register, Volume 38, Issue 24, September 1, 2021, eff. 9/11/2021