catchment vs river basin

catchment

noun
  • Any structure or land feature which catches and holds water; the collection of such water. 

  • A catchment area, or the people it serves. 

verb
  • To divide into catchment areas. 

river basin

noun
  • An extent of land where water from rain or snow melt drains downhill into a river or series of rivers. 

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