https://www.scientificamerican.com/article/after-a-14-billion-upgrade-new-orleans-levees-are-sinking/ > The $14 billion network of levees and floodwalls that was built to protect greater New Orleans after Hurricane Katrina was a seemingly invincible bulwark against flooding. > But now, 11 months after the Army Corps of Engineers completed one of the largest public works projects in world history, the agency says the system will stop providing adequate protection in as little as four years because of rising sea levels and shrinking levees.