catchment vs sump

catchment

verb
  • To divide into catchment areas. 

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

  • A catchment area, or the people it serves. 

sump

verb
  • Of a cave passage, to end in a sump, or to fill completely with water on occasion. 

noun
  • The crankcase or oil reservoir of an internal combustion engine. 

  • The lowest part of a mineshaft into which water drains. 

  • A hollow or pit into which liquid drains, such as a cesspool, cesspit or sink. 

  • A completely flooded cave passage, sometimes passable by diving. 

  • The pit at the lowest point in a circulating or drainage system (FM 55-501). 

  • An intentional depression around a drain or scupper that promotes drainage. 

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