-Han Meyer is Professor of Urban Design at Delft University of Technology.  He has been a principal organiser of the ‘Dutch Dialogues’ with New Orleans since 2005 and is Editor of ‘New Orleans-Netherlands:  Common Challenges in Urbanised Deltas’. The opinions expressed are his own.-

In August 2005, Hurricanes Katrina and Rita devastated large swathes of the U.S. Gulf Coast and overwhelmed New Orleans causing what then-U.S. Secretary of Homeland Security Michael Chertoff described as “probably the worst catastrophe, or set of catastrophes" in U.S. history.

Katrina’s punishing storm surge, strong winds and massive rainfall weakened flood protection infrastructure which then failed, flooding coastal areas of Louisiana and Mississippi, including 80 percent of New Orleans:

    Tragically, at least 1,836 people lost their lives, while a massive 1.3 million residents were evacuated, some never to return. The scale of the carnage is underlined by the fact that U.S. federal disaster declarations covered some 90,000 square miles, an area almost as large as the United Kingdom. The U.S. Geological survey has estimated that some 217 square miles of land was transformed to water by Katrina and Rita. The economic impact of the crisis has been estimated at some 150 billion pounds, with around 81 billion dollars in property damage alone.

The disaster was not only the costliest in U.S. history, but also served as a major warning for all urbanised deltas across the world of the need to maintain sufficient and efficient flood defences and water management systems.  As such, one of the biggest questions raised in New Orleans itself since 2005 has been how, and indeed whether, the city should be reconstructed and redeveloped given the threat it will continue to face from future hurricanes and catastrophic flooding.

This debate has not only prompted major interest from U.S. planners, engineers and designers, but also public authorities and politicians too, including Louisiana Senator Mary Landrieu, about international best practice, especially the pioneering ‘Dutch tradition’ of combining water management with urban development.