  It is shown that surface waves propagating against the external current,
slowly varying in the horizontal direction in deep water, are governed by the
equation which is tantamount to the Gross - Pitaevskii equation modelling the
mean-field dynamics of Bose - Einstein condensate. The repulsive or attractive
sign of the cubic term in the Gross -Pitaevskii equation is controlled by the
choice of the carrier wavelength of the surface waves, while the spatial
variation of the current plays the role of the external potential in that
equation. The current profile can be easily controlled in the experiments by
small variation of the bottom profile, so that the corresponding effective
potential in the Gross - Pitaevskii equation can be made in the form of a well
or hump. It is shown that the phenomenon of the Bose - Einstein condensation
can be effectively emulated in relatively simple laboratory setups for water
waves. Generating perturbations with an appropriate carrier wavelength, one can
create patterns in the form of trapped waves which correspond to pinned states
of Gross - Pitaevskii equation with local potentials. The estimates demonstrate
that the parameters of bottom profile, background current, and surface waves
are quite accessible to laboratory experiments.
