Illinois River at Valley City, IL: flow right now vs. normal
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—flow right now
—of typical for this month
—gage height
The Illinois River at Valley City, IL gauge has averaged 23,196 cfs over 88 years of monthly records. Flow is usually highest in May (37,352 cfs) and lowest in September (11,639 cfs).
Typical flow by month
Highest in May (37,352 cfs), lowest in September (11,639 cfs).
Key figures
- Average flow
- 23,196 cfs
- Highest peak on record
- 123,000 cfs
- Year of that peak
- 1943
- Drainage area
- 26,743 sq mi
- Years of records
- 88
- Gauge elevation
- 418 ft
- River
- Illinois River
- County
- Scott
- State
- Illinois
Monthly numbers
| Month | Average | Median | Lowest | Highest |
|---|---|---|---|---|
| Jan | 21,698 cfs | 16,000 cfs | 5,000 cfs | 78,500 cfs |
| Feb | 24,329 cfs | 20,175 cfs | 4,000 cfs | 62,250 cfs |
| Mar | 34,720 cfs | 31,400 cfs | 9,720 cfs | 100,000 cfs |
| Apr | 37,098 cfs | 34,625 cfs | 9,075 cfs | 93,100 cfs |
| May | 37,352 cfs | 34,450 cfs | 9,680 cfs | 89,000 cfs |
| Jun | 31,228 cfs | 25,750 cfs | 6,115 cfs | 87,950 cfs |
| Jul | 22,849 cfs | 18,500 cfs | 3,820 cfs | 96,700 cfs |
| Aug | 12,763 cfs | 10,800 cfs | 5,100 cfs | 52,400 cfs |
| Sep | 11,639 cfs | 7,945 cfs | 4,995 cfs | 68,850 cfs |
| Oct | 12,489 cfs | 7,810 cfs | 4,160 cfs | 54,900 cfs |
| Nov | 14,574 cfs | 11,225 cfs | 4,535 cfs | 63,600 cfs |
| Dec | 17,772 cfs | 13,850 cfs | 5,240 cfs | 77,400 cfs |
Monthly averages of daily flow over the gauge's record. Lowest and highest are the extreme monthly averages for that month.
How Illinois River at Valley City, IL compares in Illinois
- Illinois River at Valley City, IL ranks #7 of 189 gauges in Illinois in this dataset by average flow.
- That places it in the top 4% in Illinois by average flow.
- The median average flow of gauges in Illinois is 99.5 cfs.
- Among all 2,293 gauges in the dataset, Illinois River at Valley City, IL ranks #25 by average flow.
Data: U.S. Geological Survey (USGS) (public domain, U.S. federal data).· Updated 2026-11-02 · Text generated from the data and checked against it.
Live values are provisional USGS data. Measurements only, not a safety assessment — for flood warnings see the National Weather Service. Official page: USGS 05586100.