Reservoir
The reservoir is a symbol of liberty. Parents restrict their children from going near the reservoir because it is dangerous. However, the narrator and his fellow children go against their parents' orders to explore the reservoir and see what is there. The children's decision to disobey their parents illustrates their liberty to make individual decisions. The children know that the reservoir might be dangerous, but they decide to take the risk and explore it anyway.
The creek
The creek symbolizes human’s misapprehension of nature. The children know the creek very well and consider it their playground. When they follow the creek, it leads them into the reservoir where the water source is. However, a bull abruptly attacks the children, and they decide to control its anger. When the bull walks away, the children realize they can no longer locate the creek they initially claimed to know very well. Therefore, the children no longer own the creek because it is the force of nature. Interestingly, the lesson the children learn is that the creek does not follow human rules.
The charging bull
The charging bull is a symbol of the forces of reality. When the bull threatens to attack the children, they lose the creek's sight, and when they return, they are confronted with reality. The reality is that nature will never follow human will. Instead, nature has its rules that human beings must follow, which is quite contrary to the children's expectations.
