Studies have shown that real-time control (RTC) of pressure in water distribution networks (WDNs) can be very effective for leakage reduction. The aim of RTC is to regulate the pressure level over the WDN by guaranteeing a pressure that is nearly constant and as low as possible at the critical node. To this end, a pressure reducing valve (PRV) at the network inlet can be remotely controlled to ensure the optimal service level, regardless of upstream pressure and inflow. Field experiments in a district of Benevento, Italy are carried out to assess the suitability of the proposed approach. Results show that the system guarantees the required pressure at the critical node at all times. The controller is effective in optimizing pressure levels over the entire WDN by also reducing excessive pressure in the other nodes. Experiments show that the pressure control is effective in reducing leakage, as confirmed by the minimum night flow (MNF) measurements.

In this paper, considering time-averaged velocity as a random variable, two-dimensional (2D) velocity distributions in open-channel flow have been derived based on the Shannon entropy concept and the principle of maximum entropy. The velocity distributions so derived have limited practical use, since they contain too many parameters that need to be experimentally calibrated and hence are not convenient to apply. This work develops a new entropy-based approach for deriving a 2D velocity distribution in open-channel flow, thereby investigating a rectangular geometric domain. The derived distribution is parsimonious, and the values determined using the proposed distribution are found to be in good agreement with the experimentally-measured velocity values.

One of the main issues arising during the rapid filling of a pipeline is the pressure transient which originates after the entrapped air has been expelled at the air release valve. Because of the difference in density between water and air, a pressure transient originates at the impact of the water column. Many authors have analyzed the problem, both from the theoretical and the experimental standpoint. Nevertheless, mainly vertical or horizontal pipelines have been analyzed, whereas in real field applications, the pipe profile is a sequence of ascending and descending pipes, with air release/vacuum valves at high points. To overcome lack of knowledge regarding this latter case, laboratory experiments were carried out to simulate the filling of an undulating pipeline, initially empty at atmospheric pressure. The pipe profile has a high point where an orifice is installed for air venting, so as to simulate the air release valve at intermediate high point of a supply pipeline. In the experiments, the diameter of the orifice and the opening degree of both upstream and downstream valves were varied, in order to analyze their effect on the pressure transient. The experiments were also carried out with a longer descending pipe, in order to assess the effects on the pressure surge of the air volume downstream of the orifice.

In recent years, the opportunity of coupling a pressure management strategy with power generation in water distribution networks (WDNs) has attracted increasing interest. Numerical simulations developed for a number of real cases showed attractive profits and capital payback periods. Although many micro- and pico-hydro plants currently are operating along supply water mains, installations in WDNs are quite uncommon because of the high variability of flow and pressure patterns. Aiming at robust and effective industrial-based solutions, a laboratory prototype was developed for hydropower generation in WDNs. A pump as turbine (PAT) was used for generation, although a traditional turbine could be used as well. A control strategy was developed and implemented for automatic setting of regulating valves, aimed at both ensuring adequate pressure over the network and maximizing electric power. Experiments showed that the valves, equipped with the automatic control system previously described, can automatic...