Water Distribution Network Renewal Planning

Abstract

This paper provides an overview of the authors' previous work in formulating a comprehensive approach to the important problem of water distribution network renewal planning, with a particular emphasis on the computing aspects involved. As pipes in a water distribution network age in service, they are characterized by increased frequency of breakage and decreased hydraulic capacity. The resulting service failures incur utility costs for the repair or rehabilitation of the pipe systems and consumer costs for degraded system performance. The challenge to the decision maker is to determine the most cost-effective plan in terms of what pipes in the network to rehabilitate, by which rehabilitation alternative and at what time in the planning horizon, subject to the constraints of service requirements (system reliability, service pressure, etc.) A dynamic programming approach, combined with partial and implicit enumeration schemes, was used to search the vast combinatorial solution space that this problem presents. A computer program was written to implement these concepts. A hydraulic network solver is used by the program to assure the network conformance to hydraulic constraints during the search for a solution. The outcome is a strategy that identifies, for each pipe in the network, the optimal rehabilitation/renewal alternative and its optimal time of implementation. The significance of this method is in its ability to identify an optimal rehabilitation strategy while considering the deterioration of both structural integrity and hydraulic capacity of the entire network. The best current heuristic method is limited in practical studies to a network of up to 15-20 pipe links. A more efficient heuristic method is required for implementing these principles in a larger-scale water distribution system and is the subject of current research.

Water and Wastewater Pipe Nondestructive Evaluation and Health Monitoring: A Review

“…Kleiner et al [11] classified the deterioration of pipes into structural deterioration and internal deterioration. The first occurs when the pipe resiliency and the ability to withstand stress decrease.…”

Factores de fiabilidad y eficiencia en la toma de decisiones para la rehabilitación de tuberías

“…Al realizar la operación (TFN r * TFN l ), se obtiene el correspondiente riesgo × TFN rl [0.49, 0.64, 0.81]. Una vez que se determina el TFN rl , se realiza la conversión al riesgo difuso X normalizado de las cinco-tuplas del conjunto difuso (Kleiner y Adams, 2001), obteniendo el resultado del riesgo difuso X [0, 0, 0.42, 0.48, 0.10], donde tomamos la probabilidad más alta (muy alta en la escala del nivel de riesgo), que en este caso es 0.16 (tabla 9); este valor se aplica para determinar el costo de la consecuencia de fallo, donde: MB (muy bajo), B (bajo), M (medio), A (alto), MA (muy alto).…”

Use of geospatial information system based tool for renovation and rehabilitation of water distribution systems

“…Crisis models are a group of prioritized models in which renovation program is determined based on the risk of pipe breaks and the critical effects of these accidents on the network (Deb et al, 1998). Most of the available documents are related to application of optimization procedures to identify the optimum time of rehabilitation or replacement considering hydraulic or budget constraints (Lei and Saegrov, 1998;Kleiner et al, 2001;Dandy and Engelhardt, 2006;Berardi et al, 2007;Soltani, 2009). Some models use mechanical and hydraulic reliability or water quality as the replacement criteria.…”

“…There are also a few models which determine the renovation time using hydraulic and/or GIS software. Kleiner et al (2001) determined appropriate time for pipe replacement using a mathematical analysis in which EPANET software (Rossman, 2000) was used for hydraulic simulation. According to the number of bursts occurred in the system, Poulton and Conroy (2001) used GIS to evaluate the replacement program.…”