Assessing climate change and asset deterioration impacts on water distribution networks: Demand-driven or pressure-driven network modeling?

This manuscript compares demand-driven and pressure-driven hydraulic network simulation models for assessing hydraulic capacity under uncertain scenarios. A stochastic approach is implemented assuming possible alteration of boundary conditions due to climate and socio-economic changes (i.e., the increase of peaks of customers demands), and system deterioration (i.e., the increase of pipe internal hydraulic resistances and background leakages). Two real water distribution networks located in Southern Italy are used for analyses. Results show that demand-driven analysis underestimates the hydraulic network capacity with respect to pressure-driven analysis. In fact, pressure-driven analysis assumes the components of model demands (human-based and leakage-based) as dependent on pressure status of the system, and thus returns a more reasonable number and location of critical nodes than demand-driven analysis. Furthermore, demand-driven analysis does not predict the water demand that can be realistically supplied to customers under pressure-deficient system functioning. Therefore, the use of pressure-driven analysis is advisable to support water managers to allocate budgets for planning rehabilitation works aimed at increasing the hydraulic capacity of the networks.