Engineered Levee Breaches for Flood Mitigation

Abstract

Inland flooding from excessive precipitation and surface runoff remains the cause of extensive damage, loss of property, and human suffering worldwide. In this project, an engineered levee breach was considered as a measure to mitigate floods, and design attributes of the optimal levee breach were examined. The engineered levee breach creates depression waves that destructively interfere with the flood wave to crop peak flood stages. Furthermore, the engineered levee breach permits control over flood stage at a point along a channel where flood stage reduction is most beneficial in terms of hazard mitigation. The roles of flood plain storage, breach size, flood discharge, flood duration, and breach timing in the optimal design of engineered levee breaches were examined using a shallow-water model, and a strategy to design levee breaches is obtained by scaling the model results. It is shown that substantial flood stage reduction can be achieved with an engineered breach. This approach to flood fighting could prove useful in the mitigation of relatively short, extreme floods.