Pump operations-induced transients in water distribution systems. Laboratory experiments

Pump startup and shutdown induce transients in pressurized water distribution networks (WDNs) that can cause significant pressure variations, posing a risk to the system's integrity, and potentially leading to fatigue failures. This paper presents laboratory experiments designed to study pump-induced transients in a full-scale WDN at the Water Engineering Laboratory of the University of Perugia, Italy. The experimental setup includes a network of high-density polyethylene pipelines arranged in two loops, supplied by pumps set in series. Various pump startup and shutdown scenarios were tested, and the resulting transient pressures were acquired at multiple locations in the network. Both short- and long-period analyses of the experimental pressure signals identify the most vulnerable sections of the network as those either closest to the pump station or located in smaller-diameter pipelines, where wave interactions and trapped surges amplify pressure fluctuations. Particularly under low-demand (e.g., nighttime-like) conditions, these transient waves intensify. The findings also reveal how changes in network configuration and boundary conditions can significantly influence transient dissipation rates. The results provide valuable insights for water utility managers, aiding in the identification of critical network portions and the optimization of pump operations to preserve system integrity.