May 2011 New Madrid Floodway

In response to dangerous flood levels near the confluence of the Ohio and Mississippi Rivers, the U.S. Army Corps of Engineers (USACE) activated the Birds Point-New Madrid floodway (New Madrid Floodway in USGS literature) at 10:03 pm on May 2, 2011, by detonating explosives along a stretch of the Mississippi River levee just downstream of Cairo, Illinois. The resulting inflow of water into the 130,000 acre floodway caused the Ohio river stage near Cairo to drop nearly 1/2 foot during the first hour of operation. Two additional inflow/outflow breaches were initiated at 12:40 pm on May 3 and at 2:39 pm on May 5. The USGS provided vital floodway data to the USACE and other agencies.

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The activation of the floodway, which had not occurred since 1937, provided a rare opportunity to collect a unique dataset describing a flood wave downstream from a levee breach as well as the flow through a large floodway.

Streamflow data

Gage height (stage) hydrographs

Streamflow Measurements near the New Madrid Floodway (tabular data).

Select the station number below to jump to an NWIS summary of all measurements at that station.

• Ohio River at Metropolis (03611500)
• Mississippi River at Thebes (07022000)
• Mississippi River above Cairo (370000089122601)
• Ohio River at Cairo (365939089084601)
• Upper Inflow Breach at Birds Point (365659089073101)
• Mississippi River below Ohio confluence (365730089063001)
• Middle Breach (IFOF#1, 363740089180601)
• Combined Outflow (363618089251701)
• Lower Outflow Breach (IFOF#2, 363454089285900)
• Lower Outflow Gap (363524089302700)
• Mississippi River at Tiptonville (362216089303901)

Velocity Maps of the Mississippi River/Ohio River Confluence before and after the breach on May 2, 2011.

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Timeline for flood crests

The map below shows the National Weather Service's flood crest predictions along the Mississippi River as of Wednesday, May 4, 2011.

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Water-quality Measurements

USGS Activities in the News:

• Corps to Repair Birds Point Levee 

• Corps shifts focus to East Prairie after final Birds Point breach 

• Final levee breach completed in plan to stem flooding in central U.S. 

• America’s two “Great Rivers” flood at the same time