Soil and Crop Damages As a Result of Levee Breaches On Lower Mississippi River.

Extreme flooding events such as the 2008 and 2011 floods along the Mississippi and Ohio rivers and their tributaries well illustrate the continuing challenges of public (US Army Corps of Engineers) and private levee districts attempts to anticipate risk and manage emergency and evolving natural disasters associated with downstream flooding and increased pressure on levee protected bottomlands. Further, there is substantive evidence that the frequency and severity of extreme weather events is increasing leading to expectations that 50, 100 and 500 year flood events will occur more often. Of particular concern is the vulnerability of low-lying deltaic environments which are levee protected and the direct impacts of levee breaching on soil erosion, land scouring, sediment contamination and distribution and the indirect impacts on socio-economic activities, particularly agriculture, of flooded areas. Natural and induced levee breaches can result in soil contamination and agricultural crop damages. As floodwaters coat land inside former levee-protected landscapes, sediment-laden waters deposit a variety of pollutants, nutrients and contaminants that can substantively alter the productivity of the area. We discuss Birds Point-New Madrid floodway study of 2011 flooding and man-induced levee breaches on the Lower Mississippi river with attention to the impacts on soil properties and productivity as a result of craters, gullies, land scouring and sediment contamination and deposition. The characterization and measurement of flooded soils and contaminated sediment offer valuable guidance to remediation approaches and levee management decision-making. 1