Answer:
The watershed simply restricts the movement of water toward one side, because the water can not move up but only down or on a flat area.
Step-by-step explanation:
The watersheds represent physical boundaries that are separating the flow of water to rivers, seas, areas, or to put it simply, they direct the movement of water in different directions. The watersheds are marked by landforms that are at a higher elevation than their surroundings, and the separation of the movement of water occurs at the ridges.
Basically, the water moves downward on each side of the ridge. This means that the water on one side of the ridge belongs to one watershed as its waters go in one direction and area, while the water on the other side of the ridge belongs to another watershed because its waters move in another direction and area.