What causes a levee to fail?
Most levee failures can be attributed to one of three mechanisms. The first is sideways hydrostatic pressure, which essentially “pushes over” the levee from the high water side. This usually means that the levee is not massive enough. The second is seepage of water through or beneath the levee, which leads to “erosion from the inside out.” Such failures usually mean that the levee was not water resistant enough. The third kind of failure is known as overtopping, during which waves splash over the top of the levee and erode them from the outside inwardly. What caused the levee to fail during Katrina? An investigation into the cause of the levee failure continues. An initial report attributed the failure to water overtopping and washing the levee away. It is also possible that hydrostatic pressure, or under seepage through the levees, contributed to or even caused the failure. It is my opinion, based on limited data I have seen, is that under-seepage likely played a significant role – we
