According to Nolan the flood in the Japanese castle in the beginning of the film, was a challenge for Cobold ( Special Effects Supervisor) to put on film. Putting the performers in the middle of a very real and powerful event.
Corbould had a plan to use big metal shipping containers full of water, using a
dump tank method to do the scene.But it became immediately apparent that they
wouldn’t be able to have the actors anywhere near it, let alone the stunt
performers.
What the Effect Supervisor and his people came up with was “an
extremely clever method of using air cans.” Corbould explained that the
flooding was achieved by using underground pressurized containers which were
hit sequentially (forcing water out of containers up over the set). Because the
water was coming from about 20 feet above, it created the impression of a wave
coming towards camera. They wanted an atomized look, rather than a big dump of
water and as Corbould explained, it’s a shot you have to get right the first
time.
By Syed Mushfiq Hyder