The dike system cannot be counted on to protect against flooding during a significant weather event such as a direct hit from a hurricane or torrential rain event. Although there was little new information tonight, three significant facts remain.
1. The levee is expected to fail. I know that sounds bad, and it is. FEMA is apparently planning to update flood assessments this summer and redraw flood maps for Palm Beach and Martin counties. These flood maps are expected to be drawn as if the levee around Lake Okeechobee didn’t exist. In other words, they are not counting on the levees to protect against flooding.
2. The Herbert Hoover Dike is in the highest failure category of the Army Corps risk scale. Current efforts are being directed at reducing the risk category, but as it stands (and even after millions of dollars worth of improvements) the levee protecting the area still carries the highest risk classification (DSAC 1) of any dam in the United States.
3. There is no emergency spillway, nor is one planned to be built. There is no good, controlled way to drain off excess water from the lake should a large amount of rain fall in a short amount of time. Lake Okeechobee fills six times faster than it can be drained, and a foot of rainfall would result in 3 to 4 feet of water rise in the lake. Current levees will start to fail when the lake rises above 18.5 feet above mean sea level (it’s at roughly 14 feet currently), and significant levee problems are almost certain to occur when the lake reaches 20 feet over MSL.
Efforts to return the levee system to the original level of protection are expected to be completed…in 2017. However, the original design was done in the early 1930’s to 1950’s, hardly state of the art and surely not rated to withstand another hurricane season like 1926, 1928, 1945 or 1947.
I know I am not breaking any news here, but the Herbert Hoover Dike will fail, and significant parts of south Florida will be inundated with Lake Okeechobee flood waters. The question isn’t if, it’s when.