| |
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
|
6,161
|
5,297
|
4,386
|
1,734
|
10,190
|
5437500
|
|
Rock River near Joslin
|
9,549
|
86
|
9,842
|
8,646
|
7,147
|
3,128
|
17,450
|
5446500
|
|
Pecatonica River at Freeport
|
1,326
|
111
|
1,701
|
1,153
|
942
|
388
|
2,218
|
5435500
|
|
Green River near Geneseo
|
1,003
|
90
|
2,032
|
1,015
|
857
|
242
|
2,380
|
5447500
|
|
Edwards River near New Boston
|
445
|
91
|
1,435
|
503
|
374
|
68
|
1,241
|
5466500
|
|
Kankakee River at Momence
|
2,294
|
113
|
4,257
|
2,320
|
2,075
|
1,002
|
3,931
|
5520500
|
|
Iroquois River near Chebanse
|
2,091
|
103
|
3,858
|
2,282
|
1,726
|
328
|
4,963
|
5526000
|
|
Fox River at Dayton
|
2,642
|
111
|
3,379
|
2,209
|
1,765
|
675
|
5,221
|
5552500
|
|
Vermilion River at Pontiac
|
579
|
83
|
2,102
|
615
|
406
|
96
|
1,612
|
5554500
|
|
Spoon River at Seville
|
1,636
|
111
|
4,049
|
1,744
|
1,138
|
284
|
3,898
|
5570000
|
|
LaMoine River at Ripley
|
1,293
|
105
|
3,657
|
1,309
|
769
|
99
|
3,090
|
5585000
|
|
Bear Creek near Marcelline
|
349
|
82
|
945
|
349
|
135
|
4
|
835
|
5495500
|
|
Mackinaw River near Congerville
|
767
|
81
|
2,657
|
804
|
619
|
117
|
1,961
|
5567500
|
|
Salt Creek near Greenview
|
1,804
|
84
|
3,749
|
1,988
|
1,411
|
486
|
3,964
|
5582000
|
|
Sangamon River at Monticello
|
550
|
116
|
1,400
|
551
|
389
|
83
|
1,241
|
5572000
|
|
So. Fork Sangamon near Rochester
|
867
|
76
|
738
|
950
|
566
|
107
|
2,539
|
5576000
|
|
Illinois River at Valley City
|
26,743
|
87
|
42,386
|
32,155
|
28,310
|
10,480
|
66,270
|
5586100
|
|
Macoupin Creek near Kane
|
868
|
98
|
440
|
627
|
348
|
58
|
1,730
|
5587000
|
|
Vermilion River near Danville
|
1,290
|
104
|
3,348
|
1,355
|
1,057
|
229
|
2,956
|
3339000
|
|
Kaskaskia River at Vandalia
|
1,940
|
56
|
2,341
|
1,807
|
1,594
|
159
|
3,826
|
5592500
|
|
Shoal Creek near Breese
|
735
|
83
|
1,051
|
587
|
323
|
59
|
1,469
|
5594000
|
|
Embarras River at Ste. Marie
|
1,516
|
114
|
5,172
|
1,455
|
986
|
215
|
3,509
|
3345500
|
|
Skillet Fork at Wayne City
|
464
|
108
|
252
|
353
|
149
|
11
|
1,117
|
3380500
|
|
Little Wabash below Clay City
|
1,131
|
111
|
3,584
|
957
|
493
|
70
|
2,578
|
3379500
|
|
Big Muddy at Plumfield
|
794
|
55
|
178
|
825
|
664
|
169
|
1,809
|
5597000
|
|
Cache River at Forman
|
244
|
103
|
145
|
223
|
155
|
9
|
538
|
3612000
|
