What does the term 'channel' refer to in a hydrological context?

In a hydrological context, the term 'channel' specifically refers to a natural water-carrying trough created by erosion, which is the process where water flows over land and, over time, erodes the surrounding soil and rock to form a pathway. This pathway can vary in size and depth and is essential for directing the flow of rivers and streams. A channel is critical for the movement of water in an ecosystem, influencing patterns of sediment transport, habitat creation, and the overall hydrology of an area.

The other options do not encapsulate the true meaning of 'channel' in this context. A ditch that carries sewage is typically an artificial structure and does not represent the natural characteristics associated with a channel. A deep lake describes a body of water that is not specifically a channel, which is oriented more towards flowing water. Lastly, a form of water storage implies a static collection of water rather than the dynamic flow characteristic of a channel.