PROJECT ALERT NOTICE (IL) Flooding in IL

Date: Tue, 23 Apr 2013 07:46:27 EDT

Summary: Flooding in IL

Flooding in IL is ongoing, but is finally beginning to subside. Streams have peaked and are beginning to recede at all stations except the lower IL River. A moderate storm system is expected to pass through IL today, but it is not expected to worsen flooding.

At least 10 USGS gages with records over 20 years have experienced new peaks-of-record in the last week. At least 26 gages experienced a <1% AEP (i.e. a 100-year Recurrence Interval) acccording to a USGS Flood Frequency report (SIR 2004-5103), and 29 streamgages are still at the National Weather Service “major” category in and around Illinois. Four gages were damaged or destroyed during this event-- all but one are now functioning correctly. One Rapid Deployment Gage (RDG) was installed at a critical, previously ungaged location. As of today, USGS made over 60 streamflow measurements during this event. Eight Technicians (including 2 from MO WSC) are still measuring streams today, focusing on the outflows of the major drainages in IL, especially the lower IL River.

Close coordination throughout the flood event has been ongoing with the Corps of Engineers, the NWS, the IL DNR Office of Water Resources, and the USGS National Flood Coordinator.

Sub-Region: Midwest; Region: Central United States