Final answer:
Changes in water temperature, chemistry, flow characteristics, and silt loads can cause one part of a watershed to impact another part. One example of this is the operation of a dam and the creation of a reservoir, which can affect the ecology and physical characteristics of the river both upstream and downstream.
Step-by-step explanation:
One part of a watershed can impact another part of the watershed through various factors such as changes in water temperatures, chemistry, flow characteristics, and silt loads. For example, the operation of a dam and the creation of a reservoir can affect the natural water habitat, leading to significant changes in the ecology and physical characteristics of the river both upstream and downstream. These changes can have an impact on the organisms living in the watershed, as well as the overall health of the ecosystem.