Major Flood
29 ft
Current Water Level
Gage Height
Loading...
Streamflow
Loading...
Last Reading
Loading...
FLOOD STAGES
Know the flood categories.
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
Moderate Flood
27 ft
Minor Flood
23 ft
Action Stage
21 ft
What Floods at Each Level
36 ft
Lockmasters house and the lower Corps building at the lock and dam begin flooding.
35.5 ft
LaGrange Road (County Highway 12) is flooded south of LaGrange Lock and Dam.
29.5 ft
La Grange Lock Road (County Road 1730N) is flooded just north of the Lock and Dam.
28.8 ft
County Road 500N south of La Grange is closed due to flooding.
24 ft
Extensive wetland acreage south of La Grange begins flooding.
23 ft
Adjacent farmland and wetlands begins flooding. Island Road across the river in western Cass County begins flooding.
20.5 ft
The lock wall is completely overtopped.
16.5 ft
The earthen part of the dam is overtopped.
15.5 ft
Normal pool level (429.0 NGVD29).
14 ft
Dam goes up at this pool level (427.5 NGVD29).
5.6 ft
At and below this height, barge traffic will need to consider lowering tonnage to avoid grounding.
Impact statements from the National Weather Service, describing what typically happens at each water level.
7-Day Water Level Chart
Loading chart data...
Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Jul 2, 2015 | 34.66 ft | 126,400 cfs |
| Apr 27, 2013 | 34.5 ft | -9,999 cfs |
| May 31, 1995 | 34.02 ft | — |
About This Gauge
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 LaGrange Lock and Dam?
The Illinois River at LaGrange Lock and Dam gauge is maintained by USGS (site 05585100) 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 LaGrange Lock and Dam?
The NWS-defined flood stage for Illinois River at LaGrange Lock and Dam is 23 feet. Action stage begins at 21 feet. Moderate flooding starts at 27 feet, and major flooding at 29 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 LaGrange Lock and Dam to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category.
Where is the Illinois River at LaGrange Lock and Dam gauge located?
The gauge is located in Brown County, Illinois at coordinates 39.9395°N, 90.5353°W. USGS site number: 05585100. Data is provided by the U.S. Geological Survey and the National Weather Service.
More Gauges on Illinois River
On This River
More Resources
Source & Notes
Data provided by: Observations courtesy of U.S. Geological Survey
- River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 24 hours into the future from the forecast issuance time.
- 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.