First I will direct you to search floating "debris in the gulf of Mexico". There are enough objects floating there that if gathered and strung along the beaches could cover all the coastlines of our country I believe. It is floating so we would not have to buy new floating barriers, all we need is nets, which could be made from shredding more of the junk out in the ocean.
"BP" didn't put it there, it came from the cities along the waterways that feed into the gulf.
Though much of it is oil products washed out of storm drains, a lot came from the "Beautiful" beaches and those "Valuable tourists" that are so afraid of getting a tar ball on their tootsies. They should come back and volunteer to help clean it if they really care!
I also propose instead of dredging sand that will destroy animal habitat we build berms of the garbage that came from those beaches in the first place. It may be ugly to say the least but it would do more for the fish and birds in the region that get trapped in it than any other thing I can think of. The wild life doesn't want it and it's only fare that the people that made it take it back and recycle it or something. They need to pay for every bit of the pollution just like "BP", all of us who let that junk float out to sea should pay for it to be cleaned up!
If an honest look at what is in the ocean was done "BP" would look like small potatoes or in this case oil byproduct pollution.