Case Study: 17th Street Canal Breach Closure Procedures

On August 29, 2005 Hurricane Katrina resulted in several breaches in the levees and flood walls protecting New Orleans. Of the 20 breaches, the 17th Street Canal breach caused much of the city flooding. In this paper, the results of studies on a 1:50 scale hydraulic model of this breach based on the Froude similitude relationships are presented. It is assumed in the model that the bed is fixed and the levee below the flood wall remains intact during breach closure. This was the case in the 17th Street Canal breach. Because of the many uncertainties in the values of various variables, a range of conditions were run on the model in an attempt to bracket the results for the flooding depths and the initial failed attempts to close the breach. Then, various possible methods for breach closure were investigated utilizing the procedures developed for cofferdam closure for river diversion, e.g., toe dumping, transverse dumping, single- and multibarrier embankments, etc. Closures of the breach and the closure of the canal at the Old Hammond Highway Bridge were investigated. Results from the case study show that some of these methods could have been utilized for closing the Katrina breaches. However, special care should be exercised when extending them for breach closure at other sites.