Comment on the writer's advice that the backwater is charming, but no one should attempt to row up it?

While at the Sunbury Lock, J. attempted to row "up" by pulling the boat as hard as he was capable. Five minutes later, he was in the exact same spot as when he started. He was quite embarrassed and said that he doesn't try to pull up backwaters in strong streams anymore..... he leaves that work for someone else. (Pages 82 & 83)