| |
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
|
2,939
|
4,255
|
3,594
|
1,739
|
7,336
|
5437500
|
|
Rock River near Joslin
|
9,549
|
86
|
6,811
|
7,076
|
5,911
|
2,705
|
12,660
|
5446500
|
|
Pecatonica River at Freeport
|
1,326
|
111
|
N/A
|
1,155
|
909
|
434
|
2,317
|
5435500
|
|
Green River near Geneseo
|
1,003
|
89
|
N/A
|
807
|
711
|
131
|
1,545
|
5447500
|
|
Edwards River near New Boston
|
445
|
91
|
N/A
|
384
|
321
|
52
|
791
|
5466500
|
|
Kankakee River at Momence
|
2,294
|
111
|
N/A
|
2,624
|
2,548
|
1,073
|
4,482
|
5520500
|
|
Iroquois River near Chebanse
|
2,091
|
102
|
N/A
|
2,631
|
2,159
|
381
|
6,256
|
5526000
|
|
Fox River at Dayton
|
2,642
|
111
|
N/A
|
2,195
|
1,940
|
618
|
4,020
|
5552500
|
|
Vermilion River at Pontiac
|
579
|
83
|
N/A
|
551
|
427
|
47
|
1,401
|
5554500
|
|
Spoon River at Seville
|
1,636
|
111
|
313
|
1,464
|
1,336
|
241
|
2,936
|
5570000
|
|
LaMoine River at Ripley
|
1,293
|
104
|
N/A
|
1,030
|
744
|
121
|
2,197
|
5585000
|
|
Bear Creek near Marcelline
|
349
|
81
|
N/A
|
263
|
171
|
16
|
603
|
5495500
|
|
Mackinaw River near Congerville
|
767
|
81
|
35
|
684
|
540
|
64
|
1,616
|
5567500
|
|
Salt Creek near Greenview
|
1,804
|
84
|
324
|
1,738
|
1,371
|
260
|
4,359
|
5582000
|
|
Sangamon River at Monticello
|
550
|
115
|
N/A
|
599
|
445
|
52
|
1,345
|
5572000
|
|
So. Fork Sangamon near Rochester
|
867
|
76
|
304
|
875
|
600
|
31
|
2,068
|
5576000
|
|
Illinois River at Valley City
|
26,743
|
87
|
9,366
|
25,655
|
23,995
|
8,753
|
48,910
|
5586100
|
|
Macoupin Creek near Kane
|
868
|
97
|
N/A
|
745
|
460
|
39
|
1,752
|
5587000
|
|
Vermilion River near Danville
|
1,290
|
104
|
N/A
|
1,524
|
1,099
|
229
|
3,308
|
3339000
|
|
Kaskaskia River at Vandalia
|
1,940
|
56
|
1,046
|
2,786
|
2,398
|
459
|
5,650
|
5592500
|
|
Shoal Creek near Breese
|
735
|
83
|
411
|
898
|
588
|
85
|
2,147
|
5594000
|
|
Embarras River at Ste. Marie
|
1,516
|
114
|
611
|
1,964
|
1,609
|
240
|
4,117
|
3345500
|
|
Skillet Fork at Wayne City
|
464
|
107
|
808
|
673
|
511
|
49
|
1,758
|
3380500
|
|
Little Wabash below Clay City
|
1,131
|
111
|
1,014
|
1,561
|
1,183
|
163
|
3,683
|
3379500
|
|
Big Muddy at Plumfield
|
794
|
55
|
1,656
|
1,064
|
1,068
|
198
|
2,048
|
5597000
|
|
Cache River at Forman
|
244
|
103
|
1,204
|
514
|
437
|
78
|
970
|
3612000
|