What is a watershed?

A watershed is defined as an area of land that drains rainwater or snowmelt into a single body of water, such as a river, lake, or ocean. This hydrological concept is important in geography because it illustrates how water moves across landscapes and connects different ecosystems. Watersheds play a critical role in managing water resources, controlling flooding, and maintaining the health of aquatic environments.

This concept can also help in understanding environmental issues like pollution and land use. For instance, activities in a watershed—like agriculture, urban development, and forestry—can directly impact the quality and quantity of water in the body it drains into. Understanding watersheds is crucial for effective environmental management and conservation efforts.

The other options do not align with the definition of a watershed. A region that is permanently flooded refers to areas like wetlands, while the method of planting trees for air quality pertains to reforestation or afforestation, and geological formations found in mountains relate to earth science and not to the hydrological concept of watersheds.