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Illinois Administrative Code (Last Updated: March 27, 2024) |
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TITLE35. ENVIRONMENTAL PROTECTION |
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PART303. WATER USE DESIGNATIONS AND SITE-SPECIFIC WATER QUALITY STANDARDS |
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SUBPARTC. SPECIFIC USE DESIGNATIONS AND SITE SPECIFIC WATER QUALITY STANDARDS |
§303.341. Mississippi River North Central Temperature
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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 ºC (3 ºF).
a) In the Mississippi River from the Rock River to the Iowa/Missouri border:
ºC
ºF
ºC
ºF
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:
ºC
ºF
ºC
ºF
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
(Source: Amended at 47 Ill. Reg. 4575, effective March 23, 2023)