Big Sky View of the Big Spring Floods: 2011 Mississippi River Flood Imagery

By Seyi Fayanju, Environmental Defense Fund

When you hear about the floodwaters coursing through the Mississippi River Valley, it’s hard to visualize just how much water is rushing south towards the Gulf of Mexico.  Now, courtesy of the U.S. Department of Agriculture’s Mississippi River Floods May 2011 Flickr site, the Atlantic Magazine, the U.S. Army Corps of Engineers New Orleans District’s Flood Fight 2011 Flickr site, Louisiana State University’s Earth Scan Laboratory and NASA’s Earth Observatory (to name a few), you can see the power of this spring deluge.

Aerial view of Mississippi River flood of farms, wilderness, and populated areas, on Thursday, May 19, 2011. USDA Photo by Lance Cheung.

These pictures reveal the wide band that the river has cut through cities and farmland north of the river delta.  Notice how brown the river is.  Like some bizarre pipeline from a Willy Wonka fantasy, the river streams southward with a color that ranges from caramel to chocolate depending on your perspective.  That’s because the water is channeling soil and sedimentary material from nearly 30 states (and two Canadian provinces) by the time it hits the Louisiana state line.  From there, the Mississippi River is joined by a few more tributaries before it begins to branch out.

The main channel of the Mississippi usually carries most of the river water as a result of an engineering project called the Old River Control Structure.  However, because of the heavy volume of water pushing down towards Louisiana, much of the river water has been diverted into spillways.  This relieves pressure on levees along the main branch of the river, but it leads to a dramatic increase in water and sediment flows into Lake Pontchartrain, the Atachafalaya River, and other basins near the modern Mississippi River delta.

However, the most compelling visuals of the river’s power are the satellite photos from NASA’s MODIS satellite, which reveal the extent of the sediment plumes (photo below).

May 17, 2011 Mississippi River sediment plumes, as viewed from space. Photo credit: NASA Modis imagery

This spring isn’t the first time the Mississippi River has topped its banks.  In fact, long before it was leveed off, the river routinely deposited sand and fine material near its mouth as it built what we now call coastal Louisiana.  If we could fly back in time, we would have seen the swollen river building different delta lobes over several millennia.  The interruption of this process is an important reason why the wetlands of southern Louisiana are now disappearing at a rate of an acre each hour.

Each grain of sediment that pours into deep waters of the Gulf from the main stem of the Mississippi is a lost opportunity to save Louisiana.  Under ideal conditions, a significant portion of this sediment (some estimates range as high as 30 to 70%) would build the soils of the river delta and portions of the remaining sediment can replenish the delta.  For that reason, we hope that these images from above (as well as the stories of everyday people on the ground who deal with land loss) will motivate Washington to get serious about efforts to re-engineer the Mississippi River and rescue its delta.

If a picture is worth a thousand words, we want this compelling gallery of images to send this clear message to Congress: save southern Louisiana before it’s too late.