When Hurricane Katrina slammed into New Orleans in August 2005, causing greater insurance losses than any other natural disaster in history, it became clear that a lot of the city’s flood protection engineering — walls, pumps, levees — had failed. …

When Hurricane Katrina slammed into New Orleans in August 2005, causing greater insurance losses than any other natural disaster in history, it became clear that a lot of the city’s flood protection engineering — walls, pumps, levees — had failed. …