In water resources, the unbalance between supply and demand requires solutions more and more efficient. The operational control of hydraulic networks to attend population demands during the day is a problem that has been searched for many years and until nowadays the solutions are not always optimized, resulting in flaw risks for water supply. This book presents a hybrid model that uses a non-elastic matrix method to calculate the discharges and the pressure heads in hydraulic networks for the steady state and for the extended period simulation and then uses a genetic algorithm to optimize the operational control of the calculated hydraulic network. The non-elastic matrix method can also be used to calculate the transient state. This book also brings a new approach to the objective function. Instead of minimizing any given cost, the objective function minimizes the dissipated hydraulic power sum in the whole hydraulic network for all calculation time steps of the extended period simulation. This book will be especially of interest to hydraulic engineers and researchers who study and work with hydraulic networks and to all professionals interested in optimization techniques.