A case for elevating coastal roads based on experiences from Hurricane Katrina and the Tohoku Tsunami

Abstract

Experiences from Hurricane Katrina and the Tohoku Tsunami illustrate that elevated coastal roads and railroads can be effective countermeasures to coastal flood inundation and damage. In Mississippi, a railroad embankment was reported to have limited the extent of inundation, while an at-grade coastal highway did not. In Tohoku, Japan, elevated coastal highways strongly reduced the extent of the inundation zone. A simple analysis shows that the additional expenditure required to elevate the coastal highway in Mississippi is less than 1% of the direct damages caused in the state by Hurricane Katrina, illustrating the economic benefit of elevating coastal roads as multifunctional flood defences.