“of or pertaining to river banks,” 1849, from L. riparius “of a river bank,” from riparia “shore,” later used in ref. to the stream flowing between the banks, from ripa “(steep) bank of a river, shore,” probably lit. “break” (and indicating the drop off from ground level to the stream bed), or else “that which is cut out by the river,” from PIE base *rei- “to scratch, tear, cut” (cf. Gk. ereipia “ruins,” eripne “slope, precipice;” O.N. rifa “break, to tear apart;” Dan. rift “breach,” M.H.G. rif “riverbank, seashore;” cf. riven, rift, rifle)
Some novels where a river, specifically the Thames, plays a part:
Our Mutual Friend – Charles Dickens
Offshore – Penelope Fitzgerald
Daniel Deronda – George Eliot
A Sultry Month – Alethea Hayter
Three Men in a Boat – Jerome K Jerome
There must be many others.