Final answer:
The water in the channels is best described as a river.
Step-by-step explanation:
The water in the channels described in the question is best categorized as a river. During the water cycle, after precipitation falls to Earth's surface, some of it runs off into channels, which are bodies of flowing water. This water keeps moving until it eventually reaches the ocean. Rivers are examples of channels where water flows and moves downstream, making it the most accurate choice from the given options.