The phrase "sends the river" refers to something that causes large amounts of water to flow in a certain direction. There are many synonyms for this phrase, including "directs the current", "channels the stream", and "diverts the flow". Other possibilities include "guides the watercourse", "controls the runoff", and "manipulates the course". Overall, the idea is that there is some force or mechanism at work that is actively shaping the movement of a body of water. This could be a natural occurrence, such as rainfall or geological formations, or it could be the result of human intervention, such as dams or irrigation systems.