I doubt this exact setup would do New Orleans any good, but Kevan Williams of Flagpole Magazine delivers links to some urban stormwater management ideas Seattle is working on here and here.
Seattle is a city that sees high amounts of rainfall yearly, and is making a cultural and civic committment to keeping local watersheds cleaner for environmental and economic reasons. While New Orleans has similar environmental concerns, the differences in topography really demand a different approach. I wonder what ideas might work locally.
It is good to see urban areas working on more effective and environmentally friendly water management infrastructure.