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Oklahoma Administrative Code (Last Updated: March 11, 2021) |
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TITLE 785. Oklahoma Water Resources Board |
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Chapter 46. Implementation of Oklahoma's Water Quality Standards |
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Subchapter 11. Implementation of Temperature Criteria to Protect Fish and Wildlife Propagation |
SECTION 785:46-11-2. Applicable temperatures
Latest version.
- (b) Habitat limited and warm water aquatic community.(1) In waters which are designated in OAC 785:45 to be Habitat Limited Aquatic Community and/or Warm Water Aquatic Community, no heat of artificial origin shall be added that causes the receiving water to exceed the critical temperature plus 2.8°C outside the mixing zone.(2) The temperature criterion for Habitat Limited Aquatic Community and/or Warm Water Aquatic Community, Tc, is the critical temperature plus 2.8°C. In the absence of data, Tc is 32.24°C. Where data exist, the critical temperature is the higher of 29.44°C or the seven-day maximum temperature likely to occur with a 50% probability each year, 7T2. The 7T2 is calculated using a moving average of seven consecutive days for each year in a given record. These seven day receiving stream temperature values are ranked in descending order. An order number, m, is calculated based on the number of years of record, n, with a recurrence interval of 2 years, as m = (n+1)/2. The mth highest average temperature is the 7T2. Provided, in the segment of the Arkansas River from Red Rock Creek to the headwaters of Keystone Reservoir, the maximum temperature outside the mixing zone shall not exceed 34.4°C.(3) To implement the temperature criterion for Habitat Limited Aquatic Community and/or Warm Water Aquatic Community protection, the critical temperature also is the regulatory ambient temperature, Ta.(c) Cool water aquatic communities. In waters designated in OAC 785:45 to be Cool Water Aquatic Community, Tc is 28.9°C. To be consistent with implementation for warm water and habitat limited aquatic communities, the regulatory ambient temperature must be 2.8°C less than Tc. Therefore, Ta = 26.1°C for cool water aquatic communities.(d) Trout fisheries. In waters designated in OAC 785:45 to be Trout Fishery, no artificial heat shall be added such that the temperature in the receiving water exceeds 20°C outside the mixing zone. However, water temperatures regularly reach in excess of 20°C in Oklahoma's summers. When background levels exceed this criterion, the effluent level should equal the criterion. Therefore, the wasteload allocation for trout fisheries is 20°C.