There is a 'ditch' button that when pressed automatically closes all the various openings in the aircraft, rendering it sealed. In this case, the front exit only was used to prevent swamping from the rear. The plane remained floating at least 5 minutes before some settling began.
As for discussing survivability, lets look at the 'injuries' which were hypothermia.I am saving for a specially made survival suit for air travel. You can view it @ www.bookster1uk.com

Your special survival suit is an English Tweed Jacket???

No, a three piece suit in 650 gr fabric

I worked a similar "landing" in Escambia Bay, Florida in May 1978. That involved a Boeing 727 in shallow water with the landing gear down.

We had 3 dead to deal with, 1 elderly lady, wearing a lifejacket, successfully egressed to then die of Cardiac Siezure; and 1 young lady (Francis Lane) and an older gentleman who both egressed from the stbd aft hatch without life jackets. The divers recovered both of them from under the stbd engine.

The belly was ripped open but the aircraft was lifted onto a barge, taken to Pensacola Naval Airstation, and repaired enough to fly out to a commercial repair facility.

In both of these instances, a towboat (in 1978) and tugboats (today), were on the scene where the "landings" occurred and they were largely responsible for the safe recovery of most of the passengers.

Aces for the pilots and crew.

Fly-by-wire is great but they doesn't actually fly the plane during ditching. Cruising at altitude and routine takeoffs and landings it can help with and it takes a good part of the workload off the pilots. It works to keeps the pilots from doing anything overtly stupid like exceeding the flight envelope the frame can handle.

In this case I think the pilots can take pretty much 100% of the credit for remaining calm, sizing up the situation and executing a near textbook water landing. It wouldn't have taken much for the landing to have gone in sideways, cracked up and sunk in few seconds.

While we are handing out accolades don't overlook the stewards and stewardesses. While the pilots are working the airframe they are in charge of handling the passengers. They calm them down, reassure any they can, maintain order, provide leadership at critical moments, coaching, directing, and herding the passengers to the exits and making sure none are left behind.

The ferry pilots also get credit for being alert and rendering aid in the finest maritime tradition. They didn't have to do it. Nobody forced them and it wasn't their job but when the time came they went to help any way they could. Many passengers were reported to have stepped from the wings straight onto the boats.

Good job all.

Definitely a good job by all involved. That took what could have been a loss of life event and kept everyone safe. Great response by all rescue teams as well!

Well, that certainly seems to be the biggest thing you can control as a passenger. Dress for the weather and pack your jacket/coat under the seat in front of you not in the over head compartment, so you can actually get to it to take with you. You have no control over how the plane goes down and very little over how the crowd reacts. Of the items you're still allowed to carry on airplanes now, your clothing has the most potential to save your life immediately after a crash. Even if you aren't facing hypothermia, clothes can be improvised into tourniquets, bandages, slings and bindings for splints.

Well, at least the Airbus computer didn't get in the way this time.

Probably good it wasn't running MS Windows too.

Among many amazing aspects to this story, I'm amazed at how "gentle" the crash reportedly felt. I wonder if the pilot was able to drag the smooth underbelly on the water for any distance to bleed off some speed before protrusions like the engine intakes or wing tips hit the water? And the pilot must've been able to keep the plane straight and level to minimize any sort of cart wheeling or spinning effect as the airframe finally entered the water.