Illinois River at LaGrange Lock and Dam
Brown County, Illinois
The past week
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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.
Highest crests on record
| Date | Level | 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 | — |
More on Illinois River
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