Engineers are getting better at picking up the pieces after hurricanes and reducing the next-flood risk in devastated areas. But places vulnerable to catastrophic events generally must wait until they have been wrecked before significant risk-reduction measures are planned, funded and applied. Grand Isle berm rebuilt around geotube core. As the 2009 hurricane season opens, $14.3 billion worth of levee repairs and new defense construction is roaring ahead in the area smashed by Hurricane Katrina in 2005. Construction began in May on a massive, roughly $1.8-billion surge barrier to protect the southeastern flank of New Orleans, where the Corps of
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.