Chris endured sixty-seven days in the wild when he realized that the gentle knee-deep creek he had easily crossed had became way deeper due to the rain and snowmelt from glaciers high in the Alaska Range. Throughout the novel we see how strong of a man Chris is and how much he goes through on his journey, and this really symbolizes how he's just a man. People aren't perfect and no one can do "everything" right, we all have our flaws, imperfections, and our fears. Some people can control their fears better than others.
We come to learn that Chris isn't a good swimmer and that the Teklanika had went from a creek to a whitewater river. Chris is in fact afraid of the water. He believed that he would've been pulled into the rapids long before he could've swam across the river.
Chris wrote in his journal, "Disaster…. Rained in. River look impossible. Lonely, scared." He felt that he would've died if he attempted to cross the river. On page 170 it describes that Chris could've possibly mad it across the river before going into the rapids or catching hypothermia, if he dog-paddled and hopped along the bottom as he drifted downstream.
This is a real turning point in the novel because now Chris really begins to see that he may get stuck in the wild and that he can't leave whenever he wants. This is when reality wakes him up from this beautiful landscape and he realizes that this is the wild, where he has gone unprepared for the worst which is coming upon him.