Levee Failures and Breaches
Both natural and man-made levees can fail in a number of ways. The most frequent (and dangerous) is a levee breach. Here, a part of the levee actually breaks or is eroded away, leaving a large opening for water to flood land otherwise protected by the levee. A breach can be a sudden or gradual failure, caused either by surface erosion or by subsurface weakness in the levee. A breach can leave a fan-shaped deposit of sediment radiating away from the breach, described as a crevasse splay. In natural levees, once a breach has occurred, the gap in the levee will remain until it is again filled in by levee building processes. This increases the chances of future breaches occurring in the same location. Breaches can be the location of meander cutoffs if the river flow direction is permanently diverted through the gap.
Sometimes levees are said to fail when water overtops the crest of the levee. This will cause flooding on the floodplains, but because it does not damage the levee has fewer consequences for future flooding.
Read more about this topic: Levee
Famous quotes containing the word failures:
“If there is a special Hell for writers it would be in the forced contemplation of their own works, with all the misconceptions, the omissions, the failures that any finished work of art implies.”
—John Dos Passos (1896–1970)