New Orleans: Rebuild Your Own Levees?

US Federal and State Govt agencies have in the past produced some wonderful creations. The Hoover Dam comes to mind. But then there's the New Orleans levees, and now Boston's Big Dig. Here one of my libertarian economist heroes proposes that the Fedl govt is even worse than local govts. But he doesn't explain how the fedl govt produced the magnificently successful Hoover Dam, or how the the local Boston govt wasted so much on the Big Dig. I don't know what the answer is.