Water pipe renewal using a multiobjective optimization approach

Abstract

Water utilities ensure the delivery of water to consumers through a pressured network composed of several hydraulic components: reservoirs, pipes, valves, and pumps. A right maintenance policy that takes into consideration both technical and economic factors must be applied to enhance the hydraulic performance and reliability of the water network. With the help of a multiobjective approach based on a Pareto ranking and a modified genetic algorithm, we propose a decision support model that ensures the scheduling of pipe renewal according to available financial resources. The model is based on forecasting pipe failures and evaluating future maintenance costs. Two indexes are used to measure the hydraulic deficiency in the water network after a failure occurrence. They measure the undelivered water quantity and the number of unsupplied nodes when a considered pipe is unavailable during the peak demand period. Both indices permit classification of pipes and help identify critical ones. Feasible solutions are assessed according to economic and technical objectives. The model proposes solutions that enhance the reliability of a water distribution network and reduce failure occurrences, thus giving better satisfaction to consumers.

Scheduling Renewal of Water Pipes While Considering Adjacency of Infrastructure Works and Economies of Scale

“…Dandy and Englehardt (2006) used MOGA to schedule pipe replacement (5-year time steps) on a double objective trade-off between maximizing network reliability and minimizing cost. Nafi et al (2008) used Nondominated Sorting Genetic Algorithm II (NSGA II -a type of MOGA) proposed by Deb et al (2000), to address the pipe renewal scheduling problem while considering cost and hydraulic reliability. They used the proportional hazard model (PHM) to forecast future breaks and EPANET to account for network hydraulics.…”

Sustainable Infrastructure Asset Management for Water Networks

“…Various authors have expended significant effort on developing tools for the optimization and prioritization of renovation or replacement of water main pipes, as well as network reconfiguration scenario modeling (Kim and Mays, 1994;Halhal et al, 1997;Savic and Walters, 1997;Herz, 1998;Kleiner et al, 1998a,b;Hadzilacos et al, 2000;Engelhardt, 2001, 2006;Burn et al, 2004;Saegrov, 2005;Moglia et al, 2006;Nafi et al, 2008;Nafi and Kleiner, 2010;USEPA, 2011). It can also be argued that tools developed in-house will neither necessarily provide an auditable process that will stand up to close examination by stakeholders such as regulators nor facilitate continuity of knowledge or consistency of approach.…”

Risk-Based Inspection and Rehabilitation Planning of Service Connections in Intermittent Water Supply Systems for Leakage Management in Arid Regions

“…Past studies have developed different types of risk-based rehabilitation planning tools for the proactive maintenance of water mains. Some studies used multi-objective opti-mization as a tradeoff between the investments (rehabilitation, renewal, and replacement) and the benefits of reduction in pipe bursts [23][24][25][26]. D'Ercole et al [27] used an inputoutput analysis model for the rehabilitation planning of water mains by optimizing energy consumption, resource availability, and pressure deficit.…”