freshet vs rivulet

freshet

noun
  • A small stream, especially one flowing into the sea. 

  • A flood resulting from heavy rain or a spring thaw. 

rivulet

noun
  • A small brook or stream; a streamlet; a gill. 

  • Perizoma affinitatum, a geometrid moth. 

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