Illinois River at Seneca, IL
River level and flood forecast · La Salle County
Normal20.8 ftas of Mon 2:45 PM
The last 7 days and the forecast
NWS forecast issued Sun, Dec 31, 6 PM. Forecasts change as rain falls and as upstream water arrives.
Flood stages
| Action stage | 26 ft |
| Record crest (May 19, 2020) | 32.25 ft |
What floods at each level
From the National Weather Service, highest first.
- 36 ftBackwater causes Rat Run to threatened Main Street in Seneca.
- 35.5 ftA few residences threatened near River Road and IL-170 in Seneca.
- 35 ftRiver Road is threatened near IL-170 in Seneca.
- 33.5 ftIndustrial structures are threatened along the river west of Seneca.
- 33 ftBackwater causes Rat Run to threaten a few structures near Main Street in Seneca.
- 32 ftIL-36 (Dupont Road) is threatened along the river near Seneca.
- 31.5 ftOld Stage Road is threatened just east of Seneca.
- 31 ftBackwater causes Rat Run to overtop its banks near Main Street in Seneca.
- 28 ftOld Stage Road is threatened near the Illinois and Michigan Canal between Seneca and Morris. Agricultural land is inundated north of the river near Seneca.
- 27 ftRoadways at numerous marinas threatened along the river near Seneca.
- 25 ftWater overtops low-lying banks in Seneca.
Highest crests on record
- 32.25 ft — May 19, 2020
- 32.16 ft — May 2, 2019
- 30.78 ft — February 21, 2018
- 27.94 ft — September 29, 2019
- 27.36 ft — May 2, 2017
Recent crests: 32.25 ft (May 19, 2020) · 27.94 ft (September 29, 2019) · 32.16 ft (May 2, 2019) · 30.78 ft (February 21, 2018) · 27.36 ft (May 2, 2017)
Up and down the river, and nearby
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (SNAI2); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.