A moderately attractive female who is trashy in a very subtle way. Large fake breasts are common on a river chick. Most guys would want to hook up with her, but would never tell their friends about the encounter if it happened. There is really nothing wrong with being a river chick and it is not necessairly a completely demeaning term. River chicks often enjoy river type activites such as floating on tubes in slutty bathing suits while drinking.
That girl I banged is such a river chick. She asked me to go squirrel hunting next weekend.