Ill. Admin. Code tit. 35 § 303.351

Current through Register Vol. 48, No. 25, June 21, 2024

Section 303.351 - Mississippi River South 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 Illinois River to Alton Lock and Dam:

	°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

b) In the Mississippi River from Alton Lock and Dam to the Kaskaskia River:

	°C	°F		°C	°F
JAN.	10	50	JUL.	32	89
FEB.	10	50	AUG.	32	89
MAR.	16	60	SEPT.	31	87
APR.	21	70	OCT.	26	78
MAY	27	80	NOV.	21	70
JUN.	31	87	DEC.	14	57

Ill. Admin. Code tit. 35, § 303.351

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