I just spent the afternoon and evening in and around Venice, Louisiana--the town at the end of the Mississippi River and the staging area for many of the protection efforts going on. Venice is the epicenter for workers and volunteers going out in boats laying booms to protect the shore and marsh areas. In addition to oil workers and contractors, there were fishermen taking their own boats out into the Gulf to help. Just about everyone living around here realizes the grave threat the oil slick poses to their livelihoods and the environment. Many locals are involved in commercial fishing, shrimping, and oysters, and as the oil slick moves up the coast it will quickly threaten seafood that this industry depends on. It's good to see so many dedicated people working hard to minimize the damage from this disaster, but officials are still projecting the oil slick to have a significant impact on the marsh here.
Due to the wind strength and direction coming off of the Gulf, we're concerned that the oil slick will penetrate deep into the marsh. This is going to make prevention and cleanup much more difficult. We need to make sure all the resources of the federal government, private industry, and local volunteers are working together as smoothly as possible to help address this disaster.

Getting onto the helicopter with Plaquemines Parish President Billy Nungesser.

In Venice, Louisiana. You can see workers in the background loading lengths of boom onto a boat. These will be placed in the Gulf to help contain the spill.
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The potential ecological impact of this disaster, which seems likely at this point, is unspeakable. But I'm curious at that lack of mention on the massive impact this could have even above and beyond that horror.
As I've seen posted elsewhere, every 5 days means a million gallons of oil, and we're ten days in already.
So, the smell is not going to impact tourism significantly. New Orleans is about 80 miles from the mouth of the Mississippi. The smell will not carry that far.
The ecological impact, as you note, is the main concern. Our coast has been hammered by hurricanes, to be sure. But the majority of damage to our coastal areas is man-made. The intracoastal canal system which was developed during WW II (officially for national security purposes, but actually for the convenience of the oil industry) has introduced saltwater intrusion into our marshes which has killed off the cypress trees and grasses which stabilize the marshes and protect against the storm surges.
This spill is unfortunate and very visible, but the other damage from the continued existence of the intracoastal canal system is the biggest culprit.