The children's disobedience
The narrator and her fellow children know their parents restrict them from going closer to the reservoir, but they intentionally deny that order and visit it. Ironically, the children know that the reservoir is dangerous, but they decide to explore it to satisfy their curiosity. The parents do not expect their children to disobey orders, but they go against the rules.
The creek
The creek is not new to the children because they have always played there. Ironically, the day they decided to visit the reservoir, they lost sight of the creek when the bull attacked them. Therefore, for the first time, the children learned that the creek does not follow human rules but only follows the forces of nature.
The narrator's mother's fear of the reservoir
The narrator's mother fears the reservoir because she will never step near it. When the narrator returns from the reservoir with her friends, her mother reminds her never to go to the reservoir. Ironically, the narrator is coming from the same reservoir. She knows there is no danger and that her mother is scared of nothing.
