Animated Views has an article about the final portion of the battle at the end of Prince Caspian. They interviewed Prince Caspian’s Art Director, Frank Walsh, who provided many pictures and explanations for how things worked.
Animated Views: So, tell me, Frank. What will your last story on Prince Caspian be about?
Frank Walsh: Towards the end of Prince Caspian there is a climactic scene where the Telmarine Army, lead by King Miraz, march against the Narnians. Andrew Adamson, the director wanted to precede the final battle by setting Miraz the challenging task of having to ford a monstrous river to reach his enemy. In much the same way Julius Caesar, in 56BC, had taken his army against the Germanic tribes by a building bridge across the Rhine, so Andrew set us the task of achieving the same for his film. Caesar accomplished this task allegedly in 10 days; we had 40, accompanied by the predictable ‘flood’.