Sharp step or fall of water masses from one level to another level inferior.numericamente is identified by the difference of dimension given in meters; differ in: gross jump: difference of dimensions of the reservoir surface and turbinate water drain pipe.NET jump: differences in dimensions of the penstock of the water to the turbine and turbinate water drain pipe.Skip useful: it is which determines the real use of the energy of water flow through the turbine. is calculated from the difference between the net jump and the losses of load affecting the flow, due to the friction of the walls of the pipe and the pressure drop that experience through the various elements ( Elbows, valves, etc. ).