The pressure exerted on water flowing through a pipe (hydrodynamic pressure) or by which gravity pushes water masses against an object at depth (hydrostatic pressure). Because water is essentially an incompressible fluid, it can pass on the pressure exerted on it. This is used, for example, in hydroelectric power plants, where water from the bottom of a deep reservoir gushes under pressure onto a turbine. Pressure energy is then transformed into kinetic energy.