Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 303 - WATER USE DESIGNATIONS AND SITE-SPECIFIC WATER QUALITY STANDARDS
Subpart C - SPECIFIC USE DESIGNATIONS AND SITE SPECIFIC WATER QUALITY STANDARDS
Section 303.351 - Mississippi River South Central Temperature
Current through Register Vol. 48, No. 38, September 20, 2024
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 |