Question

Quick question: do water waves travel fast or slow in a shallow medium?

Answer 1

They travel faster. This is why tsunami appear as low waves on the open sea and high waves near the coast.

Answer 2

Some models give \(v=\sqrt {gh}\) where h is the depth of the basin.
This is true when \(\lambda>>h\)

If not, \(v=\sqrt{\dfrac{g\lambda}{2\pi}\tanh \dfrac {2\pi\,h}{\lambda}}\)