fluvial vs hydraulic

fluvial

adj
  • Of, pertaining to, inhabiting, or produced by the action of a river or stream. 

hydraulic

adj
  • Pertaining to water. 

  • Related to, or operated by, hydraulics. 

verb
  • To mine using the technique of hydraulic mining. 

How often have the words fluvial and hydraulic occurred in a corpus of books? (source: Google Ngram Viewer )