flume vs trunking

flume

noun
  • An open channel or trough used to direct or divert liquids. 

  • A ravine or gorge, usually one with water running through. 

verb
  • To transport (logs of wood) by floating them along a water-filled channel or trough. 

trunking

noun
  • A system of ducts for cables, heating or ventilation. 

  • The movement of containers or packages between a terminal and a transporter's inland facilities, or the scheduled transportation service between locations. 

  • All the electrical and communications cables bundled together and distributed through a building. 

  • Plastic conduit or duct used to conceal and protect electrical wiring. 

  • A two-way radio technique that uses a control channel to automatically assign frequency channels to groups of user radios. 

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