Illinois River at Marseilles Lock (tailwater)
Illinois — Water Level & Flood Stage
Located in La Salle County, Illinois on the Illinois River. Live water level data from USGS, updated every 15 minutes.
Current Water Level
Gage Height
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Streamflow
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Last Reading
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This is an NWS forecast point (LID: MMOI2). Live data may be limited. View on NWS AHPS →
Flood Stages
Minor Flood
467 ft
Action Stage
466.5 ft
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
What Floods at Each Level
483.5 ft
High water levels cause Marseilles Lock to shut down.
466.7 ft
High water levels begin to impact shipping interests along the river.
Impact statements from the National Weather Service, describing what typically happens at each water level.
Low-Water Impacts
456.5
Low water levels begin to impact shipping interests along the river.
What happens as water levels drop, per the National Weather Service.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Apr 18, 2013 | 476.72 ft | — |
| Apr 18, 2013 | 476.72 ft | — |
| Sep 15, 2008 | 475.89 ft | — |
| Sep 15, 2008 | 475.89 ft | — |
| May 18, 2020 | 475.84 ft | — |
About This Gauge
NWS LID
MMOI2
River
Illinois River
County
La Salle, IL
Coordinates
41.3284°N, 88.7551°W
Get Flood Alerts for Illinois River
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of Illinois River at Marseilles Lock (tailwater)?
The Illinois River at Marseilles Lock (tailwater) gauge is maintained by USGS and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for Illinois River at Marseilles Lock (tailwater)?
The NWS-defined flood stage for Illinois River at Marseilles Lock (tailwater) is 467 feet. Action stage begins at 466.5 feet. Moderate flooding starts at N/A feet, and major flooding at N/A feet.
How do I get alerts when Illinois River rises?
Download StormCast free on Google Play, go to River Gauges, and add Illinois River at Marseilles Lock (tailwater) to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category — even when your screen is off.
Where is the Illinois River at Marseilles Lock (tailwater) gauge located?
The gauge is located in La Salle County, Illinois at coordinates 41.3284°N, 88.7551°W. Data is provided by the U.S. Geological Survey and the National Weather Service.
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On This River
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Source & Notes
Data provided by: US Geological Survey, Observations courtesy of U.S. Army Corps of Engineers
- River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 48 hours into the future from the forecast issuance time.