Lower Ninth Ward resident S.J. Thomas walks in front of the new levee wall along the Industrial Canal after assisting a neighbor prepare for Hurricane Isaac on August 28, 2012 in New Orleans, La. - 

Kai Ryssdal: The levees have held so far. And for what they cost, they should. The Army Corps of Engineers rebuilt the New Orleans levees after Hurricane Katrina to the tune of about $14 billion. So watching all the rain and wind down there today, one does wonder whether New Orleans -- or any city, for that matter is...bear with me here: worth it?

Marketplace's Eve Troeh reports.

Eve Troeh: OK, that's beyond a loaded question. When the levees got built after Hurricane Betsy in 1965, the federal, state and local government pretty much signed a contract to protect New Orleans. That contract had not been fulfilled for decades when Katrina hit, because New Orleans had gone so long without a big storm.

Robert Meyer: In the absence of a disaster, there's not really much of a political appetite to spend billions of dollars.

Robert Meyer teaches risk management at the Wharton School. He says when you compare the cost of levee repairs to the tens of billions in damage from levee failures, or the loss of all the economic activity in New Orleans:

Meyer: $14 billion in the long-run is actually pretty cheap.

So, as we watch New Orleans levees seemingly hold up to Isaac, have we learned a collective lesson about cost, benefit, and risk?

Not if you're David Gutierrez. He's chief of safety for dams in California, and right now he needs money to prevent disaster.

David Gutierrez: Billions and billions of dollars to fix the levees here in the central valley of California.

At least $14 billion, he says, to protect a huge chunk of the state from seasonal flooding. So far, he's got a fraction of that amount.

Gutierrez: Trying to convince the public, the federal government or the state government that we have to take action is absolutely always something that we're struggling with.

California's been denied federal funding to fix levees. Even though those levees protect half a million people and $47 billion in property, there's just not the will to spend all that money to prevent something that hasn't happened. Yet.

I'm Eve Troeh for Marketplace.

Follow Eve Troeh at @evetroeh