I´ve been surfing a nice river mouth here at Portugal..
But before i write about that i want to write about La Graviere, France.
Name came from the old times before the coast law(as i learned with master journalist surfers Archi ).
Big trucks was getting the sand to use for construction as at Graviere the sand is from la Grave that means those small rocks used for construction and why the name had keep it there for ever .
Don´t know if the bank becomes more hard or less harder but makes little sound when you eat a wave and you have your face by the bottom , clink clink clink!
one thing i believe is as the sand bank always move with big swells the small rocks should be harder to move..
Graviere wasn´t working for many years but looks like will be there for many now..