Ill. Admin. Code tit. 35 § 303.341

Current through Register Vol. 48, No. 49, December 6, 2024

Section 303.341 - Mississippi River North Central Temperature

Instead of the standards of 35 Ill. Adm. Code 302.211(e), the water temperature at representative locations in the main river of the Mississippi River in the indicated locations must not exceed the maximum limits in the following tables during more than 1% of the hours in the 12-month period ending with any month. The water temperature at these locations must not at any time exceed the maximum limits in the following table by more than 1.7°C (3 °F).

a) In the Mississippi River from the Rock River to the Iowa/Missouri border:

	°C	°F		°C	°F
JAN.	7	45	JUL.	30	86
FEB.	7	45	AUG.	30	86
MAR.	14	57	SEPT.	29	85
APR.	20	68	OCT.	24	75
MAY	26	78	NOV.	18	65
JUN.	29	85	DEC.	11	52

b) In the Mississippi River from the Iowa/Missouri border to the Illinois River:

	°C	°F		°C	°F
JAN.	7	45	JUL.	31	88
FEB.	7	45	AUG.	31	88
MAR.	14	57	SEPT.	29	86
APR.	20	68	OCT.	24	75
MAY	26	78	NOV.	18	65
JUN.	30	86	DEC.	11	52

Ill. Admin. Code tit. 35, § 303.341

Amended at 47 Ill. Reg. 4575, effective 3/23/2023