The Collaborative International Dictionary of English v.0.48:

Fluviatile \Flu"vi*a*tile\, a. [L. fluviatilis, fr. fluvius
   river: cf. F. fluviatile.]
   Belonging to rivers or streams; existing in or about rivers;
   produced by river action; fluvial; as, fluviatile starta,
   plants. --Lyell.
   [1913 Webster]