A modest (flood damage prevention) proposal

When the Katrina rescue efforts are at last over, the inhabitants of New Orleans would no doubt want to rebuild.
Should they?
In fact, people building houses on mud hills, in flood plains, and other danger zones places a burden on the ret of society. It is their right to do as they wish with their property, but it is our obligation to see that the true costs of those decisions lay on those who opt for it. Maybe houses on the flooding riverfront should not be so common. Here's my proposal, which of course would not be popular with propery owners in risky areas:
1. A risk criteria will be federally established, defining areas as low, medium, and high risks.
2. All building in medium and high risk area will require adherance to standards (we have this, but the standards are low)
3. All sale and rent of property (houses and land) in medium or high risk must have the seller disclosure and the buyer's written acknoledgement (e.g. a line in the contract) that the property is in a high risk area. Not doing so is a criminal offense.
4. All built properties in medium and high risks should be assessed a federal 'mandatory rescue costs' tax, maybe 0.25% or more. This should be structured so over time, those taxes would pay the cost of rescue, federal help, and other damages to the US economy from building in those areas.

That's it. Maybe half of New Orleans should not have been built on. and no, federal help for drainage or levy building was not appropriate. If the true cost of a $100,000 home in New Orleans was $100K + $30K in infrastructure cost, this cost should be borne by those living there, not by the entire country.