The phrase "sent the river" can be rephrased in several ways. One could say "released into the current," "let it flow downstream," or "dispatched down the waterway." Another option might be "cast upon the waves," "set adrift," or "offered to the stream." Additionally, one could use "pushed into the river," "sent upon the current," or "released to the water." These synonyms allow for a varied and expressive use of language, and can help writers avoid repetition or cliche in their descriptions of sending objects or creatures down a river.