How does the tall convict react to the army camp the prisoners are resettled to during the flood?

Throughout the entire transportation time, the tall convict hears a strange noise but cannot place it. He asks a fellow prisoner what the sound is and he cryptically answers, "The Old Man". Soon, the tall prisoner realizes the sound is the river. Even though he has lived near the river his whole life, he has never heard its power until he reached the camp. This has a profound effect on him and he states that he can paddle the river, even though he cannot.