In Bretagne,France, there's a big difference in low and high tigh, about 6 till 7 meters. I did see some different ways how the people dealed with that. I'll try to make 3 threads of that subject.
For people living in such a place it might be normal but I think for a lot here not.
This one is about floating piers. A requirement for the use of thoes floating piers is that there's enough water with low tigh.
As you can see the pier is fixed to some vertical pilars. In this case.
The construction is quite simple: a ring around the pilar connected to the pier. The stairs are fixed at the top, at the bottom they glide over the pier when water is coming up.
When the pier is along the quay then this construction will work.
George