Section 302.211  Temperature

a)         There must not be abnormal temperature changes that may adversely affect aquatic life unless caused by natural conditions.

b)         The normal daily and seasonal temperature fluctuations that existed before the addition of heat due to other than natural causes must be maintained.

c)         The maximum temperature rise above natural temperatures must not exceed 2.8 °C (5 ºF).

d)         In addition, the water temperature at representative locations in the main river must not exceed the maximum limits in the following table during more than one percent of the hours in the 12-month period ending with any month.  Moreover, the water temperature at those locations must never exceed the maximum limits in the following table by more than 1.7 ºC (3 ºF).

e)         The owner or operator of a source of heated effluent that discharges 150 megawatts (0.5 billion British thermal units per hour) or more must demonstrate in a hearing before the Board in the case of new sources, after the commencement of operation, that discharges from that source have not caused and cannot be reasonably expected to cause significant ecological damage to the receiving waters.  If this demonstration is not made to the satisfaction of the Board, the Board will order appropriate corrective measures to be implemented within a reasonable time as determined by the Board.

f)         Permits for heated effluent discharges, whether issued by the Board or the Agency, can be revised if reasonable future development creates a need for reallocation of the assimilative capacity of the receiving stream as defined in the regulation above.

g)         The owner or operator of a source of heated effluent must maintain records and conduct studies of the effluents from the sources and of their effects as may be required by the Agency or in any permit granted under the Act.

h)         Appropriate corrective measures will be required if, upon complaint filed in compliance with Board rules, it is found at any time that any heated effluent causes significant ecological damage to the receiving stream.

i)          All effluents to an artificial cooling lake must comply with the applicable provisions of the thermal water quality standards in this Section and 35 Ill. Adm. Code 303, except when all of the following requirements are met:

1)         All discharges from the artificial cooling lake to other waters of the State comply with the applicable provisions of subsections (a) through (d).

2)         The heated effluent discharged to the artificial cooling lake complies with all other applicable provisions of this Chapter, except subsections (a) through (d).

3)         At an adjudicative hearing, the discharger must satisfactorily demonstrate to the Board that the artificial cooling lake receiving the heated effluent will be environmentally acceptable, and within the intent of the Act, including:

A)        providing conditions capable of supporting shellfish, fish and wildlife, and recreational uses consistent with good management practices, and

B)        controlling the thermal component of the discharger's effluent by a technologically feasible and economically reasonable method.

4)         The required demonstration in subsection (i)(3) may take the form of an acceptable final environmental impact statement or pertinent provisions of environmental assessments used in the preparation of the final environmental impact statement, or may take the form of a demonstration under Section 316(a) of the Clean Water Act (CWA) (33 U.S.C. 1251 et seq.) that addresses the requirements of subsection (i)(3).

5)         If the Board finds the demonstration to be adequate as provided in subsection (i)(3), the Board will promulgate specific thermal standards to be applied to the discharge to that artificial cooling lake.

(Source:  Amended at 47 Ill. Reg. 4437, effective March 23, 2023)