Alzrius
The EN World kitten
You're referring to the poems "The Adventures of Tom Bombadil" and "Tom Bombadil Goes Boating," if I'm not mistaken (both of which can be found in The Tolkien Reader).Well the Withywindle does, just ask Old Tom!
There is more on this in the Tom Bombadil book.
Specifically, what verses in either of those poems do you think indicate that the river itself has its own spirit?