Un supporto nella gestione delle reti di fognatura

In Italy the storm sewer are generally evaluated in the hypotheses of uniform motion and lack of carried solid material; these hypotheses are, obviously, not in accordance with the real functioning of the main sewers, in which the water flow changes continuously in time and space and, where, problems relative to the sediment transport are relevant. The minimum values of self-cleansing velocities fixed by rules in inadequate in certain circumstances; they result lower than values adopted in other European countries, such as Germany and England. Law 36/94, which established in Italy the “Integrated Water Service”, requires principles of efficiency, efficacy and economy in the management of sewer networks hard to reach without the use of dynamic simulation models and principles of flow transportation capacity check; such models, in fact, represent the essential basis of an efficient management system. This paper proposes an analysis procedure of sewer system functioning which allows to characterize the solid transportation while passing a flood event of assigned probability and allows to identify sections which present the greatest complexities and for which maintenance interventions and functionality restoration will have to be foreseen more frequently.