Water hammer is a little-studied and often neglected phenomenon in hydraulic networks, caused by the propagation of pressure waves originating from the sudden closure of a valve, that can damage irreversibly the pipelines and other structures of the network. The system studied in this work of thesis is a square lattice hydraulic network, with a reservoir on one vertex and a valve on each of the other nodes, that can be closed to study the consequent water hammer effect. After analyzing the data obtained from different simulations of the phenomenon, a toy model based on network approach is developed to understand the underlying mechanisms of pressure wave propagation in a network and, finally, identify the cases in which such model provides a good prediction of the simulation results..