Vegetation on Levees Woody vegetation growing on a flood control
levee is perceived by many people as compromising levee
strength. The original levee structure was designed to not have
trees and shrubs growing on it. Nevertheless, there are many
miles of flood control levees in the Central Valley with trees
growing on them, due to a long history of no seepage or
structural problems apparent on or around them. However, this
situation is viewed as a threat to public safety by the US Army
Corps of Engineers (ACE), ultimately responsible for levee
performance. Examining the logic of the possible problems that
trees growing on the levee may pose has resulted in these web
pages. There is a body of research and observations that tree
roots growing into a levee support public safety by
strengthening the levee's shear strength, protecting it from
surface erosion, and discouraging burrowing rodents from
residing in the levee. These web pages examine some of the
misconceptions about vegetation on levees, describe how tr