Shorelines are temporary geologic and topographic features. Explain this statement.?

Question

Shorelines are temporary geologic and topographic features. Explain this statement.

Answer 1

shorelines are in constant motion.  Sandy beaches can be reshaped by just one major storm.  Currents are constantly shifting sand and forming new highs and lows, frequently forcing rivers to shift where they enter the sea.  This in turn forces the rivers to erode their channels differently.

Cliffs, high relief shore lines, are under attack all  the time and being force to retreat.  

Consequently any topographic map has to be constantly updated.

Huge amounts of money are spent in trying to stabilize shore lines to protect property interests, most are unsuccessful over time.