Water waves are disturbances of the free surface of a liquid. They are, in general, produced

by the immersion of a solid body or by impulsive pressures applied on the free surface. The 

two questions we discuss in this talk are the following: 

- which waves can be generated by blowing on a localized portion of the free surface ? 

Our main result with Pietro Baldi and Daniel Han-Kwan asserts that one can generate any small amplitude, periodic in x, two-dimensional, gravity-capillary water waves. 

- consider now gravity water waves in a rectangular tank. Is-it possible to estimate their energy by

looking only at the motion of some of the curves of contact between the free surface and the vertical walls