Flooding occurs when water levels rise to such a level that they cannot be contained by the river banks. The Mississippi River is susceptible to flooding in spring months because of the many tributaries that flow into it. Excess water flows into surrounding areas, known as floodplains. Many people living here understand the risks involved. However, when floods are few and far between, we tend to forget the power of that which otherwise sustains us - water.
Picture by Scott Olson
Houses stand flooded, waiting weeks for the water to recede (above and right). The Great Flood of 1927
The Great Flood of 1927 caused destruction to homes, farms, and businesses. Although levees were present, they could not contain the massive amounts of water flowing toward the Gulf of Mexico.
Picture by U.S. Army Corps of Engineers
Refugees in the 1927 flood camped in tents on top of levees, just a few feet from the waters that drowned their homes (above).
Flood of 2008
During Spring of 2008, the Mississippi River became swollen with excessive rainfall from its tributaries and snow melt from the Appalachia. Many families living near the river suffered physical loss of their homes as well as emotional burdens of displacement.
The Function of Levees
Levees are built to contain flood waters. Flood walls provide an initial safety precaution but, when built correctly and maintained, levees are able to withstand much more force of flood water.
Source: USGS, U.S. Army Corps of Engineers; Chicago Tribune
Although the Mississippi River usually carries more sediment within its currents, the Ohio River is browner in this 2006 image because the overwhelming flow of melting snow from the Appalachia picks up massive amounts of sediment as it travels to join Ol' Man River (above). Note how little mixing occurs even after the rivers converge near Cairo, Illinois.
Picture by Scott Olson
Picture by Whitney Jackson
When levees fail, water can seep into surrounding areas in different ways - overtopping, underflow, slumping, and erosion (see below picture).