The phrase "sending the river" is not commonly used in every day language, and therefore does not have a specific antonym. However, one could consider using words such as "stopping the river" or "blocking the river" as possible antonyms. Alternatively, the phrase could be interpreted more broadly, with antonyms such as "receiving the river" or "diverting the river" being valid options. Ultimately, the antonym or opposite of "sending the river" depends on the context in which the phrase is being used, and the specific meaning that is being conveyed.