  Topological concepts have been introduced into electronic, photonic, and
phononic systems, but have not been studied in surface-water-wave systems. Here
we study a one-dimensional periodic resonant surface-water-wave system and
demonstrate its topological transition. By selecting three different water
depths, we can construct different types of water waves - shallow, intermediate
and deep water waves. The periodic surface-water-wave system consists of an
array of cylindrical water tanks connected with narrow water channels. As the
width of connecting channel varies, the band diagram undergoes a topological
transition which can be further characterized by Zak phase. This topological
transition holds true for shallow, intermediate and deep water waves. However,
the interface state at the boundary separating two topologically distinct
arrays of water tanks can exhibit different bands for shallow, intermediate and
deep water waves. Our work studies for the first time topological properties of
water wave systems, and paves the way to potential management of water waves.
