intertidal zone vs water's edge

intertidal zone

noun
  • The part of a shore between high water and low water, especially the beach exposed at maximum ebb spring tides. 

water's edge

noun
  • The edge of any body of water, such as a lake or sea. 

How often have the words intertidal zone and water's edge occurred in a corpus of books? (source: Google Ngram Viewer )