bayou vs plunge pool

bayou

noun
  • A slow-moving, often stagnant creek or river. 

  • A swamp; a marshy (stagnant) body of water. 

plunge pool

noun
  • A pool that is small in diameter, but deep, usually resulting from erosion by a natural force such as a waterfall or rapids. 

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