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Illinois River at Ottawa

Highest listed crest 473.72 ftFlood stage 463.0 ft24 crests since 2001

The Illinois River at Ottawa crested at major flood stage 4 times among the 24 crests the National Weather Service lists from 2001 to 2020. The highest, 473.72 ft on April 19, 2013, was major flooding, 10.72 feet above flood stage. 8 other gauges on the Illinois River crested above flood stage within a week of it, 8 at their own highest listed crest.

The gauge

Highest listed crest
473.72 ft
April 19, 2013
Flood stage
463.0 ft
Major flooding from 471.0 ft
Crests at major
4
65th of 177 gauges in Illinois
Most recent flood crest
May 19, 2020
472.59 ft, major flooding
Location
LaSalle County
Near Ottawa (1.1 mi)
Identifiers
NWS OTWI2
No USGS station

Flood stages

The thresholds the National Weather Service uses for this gauge today, and how many listed crests reached each.

Flood categories, Illinois River at Ottawa
Action stage461.02Oct 26, 2001The level at which the NWS or its partners begin to take action
Flood stage (minor)463.010Oct 16, 2017Minimal or no property damage, but possibly some public threat
Moderate flood stage467.08May 2, 2019Some inundation of structures and roads near the stream
Major flood stage471.04May 19, 2020Extensive inundation of structures and roads

Every listed crest

24 crests from 2001 to 2020. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Illinois River at Ottawa, 2001 to 2020 460465470475ft Flood stage 463.0 ftMajor 471.0 ft Jun 7, 2001: 462.00 ft, action stageOct 26, 2001: 461.70 ft, action stageMay 13, 2002: 468.00 ft, moderate floodingDec 12, 2005: 467.80 ft, moderate floodingDec 23, 2006: 463.10 ft, minor floodingMar 1, 2007: 463.80 ft, minor floodingJan 9, 2008: 467.60 ft, moderate floodingFeb 10, 2008: 463.50 ft, minor floodingFeb 17, 2008: 465.00 ft, minor floodingMar 3, 2008: 463.10 ft, minor floodingSep 16, 2008: 472.21 ft, major floodingDec 29, 2008: 468.87 ft, moderate floodingMar 11, 2009: 470.23 ft, moderate floodingJun 24, 2010: 464.29 ft, minor floodingApr 19, 2013: 473.72 ft, major floodingJun 17, 2015: 467.86 ft, moderate floodingDec 30, 2015: 468.06 ft, moderate floodingMar 31, 2017: 464.33 ft, minor floodingMay 2, 2017: 466.46 ft, minor floodingJul 23, 2017: 464.10 ft, minor floodingOct 16, 2017: 463.65 ft, minor floodingFeb 22, 2018: 471.49 ft, major floodingMay 2, 2019: 470.83 ft, moderate floodingMay 19, 2020: 472.59 ft, major flooding Highest, 473.72 ft, Apr 19, 2013 2005201020152020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Illinois River at Ottawa 2000s: 11 11 2010s: 10 2020s: 1 2000s2010s2020s
  1. These are the crests the local National Weather Service office lists for the gauge: the highest on record and recent crests. Lesser floods between them may be missing, so counts by decade are a floor.
  2. Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable.

Highest crests

Highest listed crests, Illinois River at Ottawa
1Apr 19, 2013473.72+10.72Major—
2May 19, 2020472.59+9.59Major—
3Sep 16, 2008472.21+9.21Major—
4Feb 22, 2018471.49+8.49Major—
5May 2, 2019470.83+7.83Moderate—
6Mar 11, 2009470.23+7.23Moderate—
7Dec 29, 2008468.87+5.87Moderate—
8Dec 30, 2015468.06+5.06Moderate—
9May 13, 2002468.00+5.00Moderate—
10Jun 17, 2015467.86+4.86Moderate—
11Dec 12, 2005467.80+4.80Moderate—
12Jan 9, 2008467.60+4.60Moderate—
13May 2, 2017466.46+3.46Minor—
14Feb 17, 2008465.00+2.00Minor—
15Mar 31, 2017464.33+1.33Minor—
16Jun 24, 2010464.29+1.29Minor—
17Jul 23, 2017464.10+1.10Minor—
18Mar 1, 2007463.80+0.80Minor—
19Oct 16, 2017463.65+0.65Minor—
20Feb 10, 2008463.50+0.50Minor—
21Dec 23, 2006463.10+0.10Minor—
22Mar 3, 2008463.10+0.10Minor—
23Jun 7, 2001462.00−1.00Action—
24Oct 26, 2001461.70−1.30Action—

The worst floods along the Illinois River

For this gauge's highest crests, the other gauges on the Illinois River that crested above flood stage within a week.

April 19, 2013: 473.72 ft here, major flooding

  • Starved Rock Lock (tailwater)IL · Apr 19, 2013 · 467.81 ft · Major · its highest
  • Peoria Lock and DamIL · Apr 23, 2013 · 456.57 ft · Major · its highest
  • La SalleIL · Apr 20, 2013 · 34.44 ft · Major · its highest
  • HenryIL · Apr 22, 2013 · 32.94 ft · Major · its highest
  • PeoriaIL · Apr 23, 2013 · 29.35 ft · Major · its highest
  • HavanaIL · Apr 25, 2013 · 27.78 ft · Major · its highest
  • MorrisIL · Apr 19, 2013 · 24.91 ft · Major · its highest
  • Marseilles Lock (tailwater)IL · Apr 19, 2013 · 476.72 ft · Minor · its highest

May 19, 2020: 472.59 ft here, major flooding

September 16, 2008: 472.21 ft here, major flooding

Gauges on the Illinois River

Flood gauges sharing the river's name, linked within 80 miles of one another.

Flood gauges on the Illinois River
BeardstownIL14.029.81 ft, Apr 27, 201310
HardinIL25.042.40 ft, Aug 3, 199320
LaGrange Lock and DamIL23.034.66 ft, Jul 2, 201517
Marseilles Lock (tailwater)IL467.0476.72 ft, Apr 19, 20130
MeredosiaIL17.028.86 ft, Jul 2, 201523
MorrisIL16.024.91 ft, Apr 19, 201312
Ottawa this gaugeIL463.0473.72 ft, Apr 19, 20134
PeoriaIL18.029.35 ft, Apr 23, 20135
Peoria Lock and DamIL447.0456.57 ft, Apr 23, 20135
Starved Rock Lock (tailwater)IL450.0467.81 ft, Apr 19, 20133
Valley CityIL14.027.00 ft, May 26, 194317
HavanaIL14.027.78 ft, Apr 25, 201325
HenryIL23.032.94 ft, Apr 22, 20137
La SalleIL20.034.44 ft, Apr 20, 20139

Other gauges in LaSalle County

Flood gauges in LaSalle County
Dayton12.036.47 ft, Jan 25, 19605
Marseilles Lock (tailwater)467.0476.72 ft, Apr 19, 20130
Starved Rock Lock (tailwater)450.0467.81 ft, Apr 19, 20133
La Salle20.034.44 ft, Apr 20, 20139
Leonore16.030.25 ft, Apr 18, 20132

LaSalle County: every hazard · River floods across the country · Illinois

NOAA National Water Prediction Service, gauge OTWI2, retrieved October 30, 2026. Stages in feet on the gauge's own datum, not elevation. Crests are as the National Weather Service lists them; preliminary values may be revised.