I think the New Orleans officials could have prevented a lot of it by actually spending the money they collect to maintain the levee system on maintaining the levees.
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Near where I live, the "big city" had a major water main break that flooded much of the downtown area...shut down a number of businesses and caused extensive damage and loss. Some of the water pipes are around 100 years old, but except in maybe a handful of places, they were never maintained. It's a wonder these pipes haven't burst long before this. But that's the problem...the city has never bothered to do anything; it has managed to squander all of its revenue to the point of being in financial distress; so now it has no money to maintain the water pipes even if it wanted to. It's only a matter of time before another break occurs.
This is what many cities do -- they make residents pay through the nose in income and property taxes, but where does that money go? Certaintly, doesn't go toward maintaining the city infrastructure.
" they make residents pay through the nose in income and property taxes, but where does that money go?"
Silly, it goes for salaries for the highly motivated, highly efficent, effective and hard working city employess most of whom are oppressed and disadvantaged "minorities" only seeking equality and a nice politically correct lifestyle.