A watershed is best described as ...

• A. An area of land where all the water that falls drains to the same place
• B. A large inland sea
• C. A network of underground rivers
• D. The top layer of soil where plants grow

Answer: (A)

A watershed is the land area where all water from precipitation drains to a single outlet, such as a river, lake, or ocean. The boundary of a watershed is set by the surrounding high ground or ridges, which separate it from neighboring basins. Water that falls anywhere inside that area—rain, snowmelt, or irrigation—will eventually flow through streams and groundwater to that shared outlet. This explains why it’s described as the area where all water drains to the same place. The other descriptions point to a large inland sea, underground water networks, or the top layer of soil, none of which define the drainage area that channels water to one endpoint.