  Nowadays hydroelectric energy is one of the best energy sources: it is
cleaner, safer and more programmable than other sources. For this reason, its
manage could not be done in an approssimative way, but advance mathematical
models must be use. In this article we consider an overview of the problem: we
introduce the problem, then we show its simplest but quite exaustive
mathematical formulation and in the end we produce numerical results under the
ipothesis that all input are deterministic.
