| |
Long-term
monthly flows for period of record (cfs) | |
| Station |
Drainage area
(sq. mi.) |
Years of record |
Monthly
mean flow (cfs) |
Mean flow* |
Median (50% exceedence) flow |
90% exceedence flow |
10% exceedence flow |
USGS Station No. |
|
Rock River at Rockton
|
6,363
|
86
|
N/A
|
4,238
|
3,564
|
1,739
|
7,336
|
5437500
|
|
Rock River near Joslin
|
9,549
|
86
|
N/A
|
7,045
|
5,894
|
2,705
|
12,660
|
5446500
|
|
Pecatonica River at Freeport
|
1,326
|
111
|
661
|
1,152
|
906
|
436
|
2,075
|
5435500
|
|
Green River near Geneseo
|
1,003
|
89
|
N/A
|
803
|
695
|
131
|
1,545
|
5447500
|
|
Edwards River near New Boston
|
445
|
91
|
N/A
|
380
|
318
|
52
|
791
|
5466500
|
|
Kankakee River at Momence
|
2,294
|
111
|
1,684
|
2,612
|
2,537
|
1,073
|
4,482
|
5520500
|
|
Iroquois River near Chebanse
|
2,091
|
102
|
N/A
|
2,608
|
2,133
|
372
|
6,256
|
5526000
|
|
Fox River at Dayton
|
2,642
|
111
|
N/A
|
2,186
|
1,915
|
618
|
4,020
|
5552500
|
|
Vermilion River at Pontiac
|
579
|
83
|
N/A
|
544
|
414
|
40
|
1,401
|
5554500
|
|
Spoon River at Seville
|
1,636
|
111
|
N/A
|
1,453
|
1,336
|
241
|
2,936
|
5570000
|
|
LaMoine River at Ripley
|
1,293
|
104
|
N/A
|
1,020
|
738
|
95
|
2,197
|
5585000
|
|
Bear Creek near Marcelline
|
349
|
81
|
2
|
260
|
171
|
14
|
603
|
5495500
|
|
Mackinaw River near Congerville
|
767
|
81
|
N/A
|
676
|
539
|
62
|
1,616
|
5567500
|
|
Salt Creek near Greenview
|
1,804
|
84
|
125
|
1,721
|
1,362
|
260
|
4,359
|
5582000
|
|
Sangamon River at Monticello
|
550
|
115
|
5
|
595
|
444
|
52
|
1,345
|
5572000
|
|
So. Fork Sangamon near Rochester
|
867
|
76
|
14
|
868
|
592
|
31
|
2,068
|
5576000
|
|
Illinois River at Valley City
|
26,743
|
87
|
9,050
|
25,470
|
23,990
|
8,753
|
48,910
|
5586100
|
|
Macoupin Creek near Kane
|
868
|
97
|
19
|
740
|
455
|
39
|
1,752
|
5587000
|
|
Vermilion River near Danville
|
1,290
|
104
|
N/A
|
1,513
|
1,090
|
229
|
3,308
|
3339000
|
|
Kaskaskia River at Vandalia
|
1,940
|
56
|
N/A
|
2,755
|
2,365
|
459
|
5,650
|
5592500
|
|
Shoal Creek near Breese
|
735
|
83
|
72
|
893
|
583
|
85
|
2,147
|
5594000
|
|
Embarras River at Ste. Marie
|
1,516
|
114
|
N/A
|
1,951
|
1,600
|
240
|
4,117
|
3345500
|
|
Skillet Fork at Wayne City
|
464
|
107
|
111
|
674
|
518
|
49
|
1,758
|
3380500
|
|
Little Wabash below Clay City
|
1,131
|
111
|
365
|
1,556
|
1,180
|
163
|
3,683
|
3379500
|
|
Big Muddy at Plumfield
|
794
|
55
|
N/A
|
1,075
|
1,077
|
198
|
2,048
|
5597000
|
|
Cache River at Forman
|
244
|
103
|
N/A
|
521
|
441
|
78
|
1,050
|
3612000
|