Changes to datum and flood impact categories for DuPage River at Shorewood, IL

Effective January 31, 2023, the datum, or gauge zero, will change for the DuPage River at Shorewood, Illinois. This will require changes to the past crests, documented flood impacts, and flood impact categories. These changes are necessary to prevent negative stage values on the gauge during periods of extended dry weather.

Click here for the service change notice issued January 17, announcing these changes.

DuPage River at Shorewood

Datum (Gauge Zero)
Change from
564.73 feet NAVD88 to
554.73 feet NAVD88

Action Stage
Change from 5.0 to 15.0 feet

Minor Flood Stage
Change from 5.5 to 15.5 feet

Moderate Flood Stage

Change from 7.5 to 17.5 feet

Major Flood Stage
Change from 9.5 to 19.5 feet

River forecasts for this location will still be issued when the water level has reached, or is expected to reach, action stage.

These changes are related to the removal of Hammel Woods Dam in late 2021. Dam removal changed the behavior of the river at the gauge location such that the river is now at lower stages when passing the same amount of water. An analysis by the US Geological Survey has indicated that stage values may go below 0 feet (negative) during periods of extended dry weather. To avoid such a situation, the datum is being changed to make stages report at higher values for the same amount of flow.

This gauge represents the river reach from near IL-59 in Plainfield to the confluence with the Des Plaines River.

Approximate Stage...

Prior to Hammel Woods Dam removal	After dam removal	After datum shift
Oct 1940 - Sep 2021	Sep 2021 - Jan 2023	Jan 31, 2023
1.5	0.0	10.0
3.5	2.0	12.0
5.2	4.0	14.0
6.0	5.0	15.0
6.8	6.0	16.0
7.6	7.0	17.0
8.5	8.0	18.0
9.4	9.0	19.0
10.4	10.0	20.0
12.3	12.0	22.0
14.3	14.0	24.0