estuary vs sandbar

estuary

noun
  • A coastal water body where ocean tides and river water merge, resulting in a brackish water zone. 

  • An ocean inlet also fed by fresh river water. 

sandbar

noun
  • A ridge of sand caused by the action of waves along a shore. 

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