Answer:
John is observing runoff.
Step-by-step explanation:
In the water cycle, runoff is the flow of water that occurs when excess water from rain, snowmelt, or other sources flows over the land surface and into streams, rivers, and other bodies of water. It is a key part of the water cycle because it moves water from the land to surface water bodies, where it can continue its journey through the cycle. So, in this scenario, John is observing runoff as he is seeing water flowing down the side of the mountain.