Major Flood
471 ft
Current Water Level
Gage Height
Loading...
Streamflow
Loading...
Last Reading
Loading...
This is an NWS forecast point (LID: OTWI2). Live data may be limited. View on NWS AHPS →
FLOOD STAGES
Know the flood categories.
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
Moderate Flood
467 ft
Minor Flood
463 ft
Action Stage
461 ft
What Floods at Each Level
476 ft
Water reaches the top of the levee at Ottawa High School.
475.5 ft
Backwater causes the Fox River to reach the top of the flood protection wall south of Main Street near Ottawa High School. Water inundates lower-level of residences at Heritage Harbor east of Ottawa.
474.5 ft
Backwater causes the Fox River to reach the top of the levee at Ottawa High School.
474 ft
Structures threatened at Shoreline Boat Club in Ottawa. Main Street at Fox River in Ottawa is threatened and may be closed, blocking the last primary evacuation route for east Ottawa. Water overtops the berm at Waste Water Treatment Plant.
472 ft
West parking lot of St. Elizabeth Medical Center in Ottawa is inundated.
471.5 ft
Water reaches top of levee at Ottawa Waste Water Treatment Plant. Backwater causes the Fox River to inundate the YMCA parking lot in Ottawa.
470 ft
Shabbona Street near Ottawa High School is inundated. St. Elizabeth Medical Center property in Ottawa is threatened including the loading dock areas.
469 ft
Backwater causes the Fox River to reach bankfull near the YMCA in Ottawa.
468 ft
River Rescue structure threatened in Ottawa.
467 ft
Green Street near Shoreline Boat Club in Ottawa is inundated, blocking a primary evacuation route for east Ottawa.
466.5 ft
Low-lying sections of Fox River Park in Ottawa are inundated including Hudson Street River Walk. St. Clair Street is threatened in Ottawa.
465.5 ft
Low-lying property near St. Elizabeth Medical Center is threatened. Marquette High School football field threatened.
465 ft
Harbor Walk in Heritage Harbor east of Ottawa is inundated.
464 ft
Backwater causes the Fox River to reach bankfull near St. Elizabeth Medical Center in Ottawa.
462.5 ft
Roadway entrance to Allen Park threatened in Ottawa. Allen Park west boat ramp inundated in Ottawa.
461 ft
River Rescue boat dock inundated in Ottawa.
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
Loading chart data...
Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Apr 18, 2013 | 473.72 ft | — |
| May 18, 2020 | 472.59 ft | — |
| Sep 15, 2008 | 472.21 ft | — |
Flood Inundation Map
NOAA has mapped what areas flood at different water levels for this gauge. View the interactive flood inundation map →
About This Gauge
NWS LID
OTWI2
River
Illinois River
County
La Salle, IL
Coordinates
41.3444°N, 88.8392°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 Ottawa?
The Illinois River at Ottawa 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 Ottawa?
The NWS-defined flood stage for Illinois River at Ottawa is 463 feet. Action stage begins at 461 feet. Moderate flooding starts at 467 feet, and major flooding at 471 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 Ottawa 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 Ottawa gauge located?
The gauge is located in La Salle County, Illinois at coordinates 41.3444°N, 88.8392°W. Data is provided by the U.S. Geological Survey and the National Weather Service.
More Gauges on Illinois River
On This River
Upstream: Illinois River at Marseilles Lock (tailwater)
Downstream: Illinois River at Starved Rock Lock (tailwater)
More Resources
Source & Notes
Data provided by: US Army Corps of Engineers
- River forecasts for this location take into account past and future precipitation. The stages/flows that will occur may be different if future rainfall is different than forecast.