"... flood defense is still lacking, people are still homeless..."

Not sure what you mean here. Everybody who applied to FEMA after hurricane Katrina was provided food and shelter. There are still people being put up in hotel rooms at taxpayers' expense, three years later. All US cities have a population of homeless, especially the warmer areas of California and some cities in the South.

As far as levee repair, contracts cannot be oppered on a "no-bid" basis (note the hysterical reaction to such contracts in Iraq). In a war, time is everything, but here at home, bids must be submitted, environmental impact reports made (that can take awhile), and construction firms are often investigated to see if they are really capable of doing the job. Construction can take years. In the case of freeways and major bridges, it can take decades.