Improving the Performance of Water Distribution Networks Based on the Value Index in the System Dynamics Framework

Abstract

This study proposes an algorithm for the improvement of water distribution networks (WDNs) performance using system dynamics. In the first part, the hydraulic and environmental performance of WDNs is investigated. The hydraulic performance is assessed based on the pressure of nodes and the flow velocity in pipes. Furthermore, using life cycle assessment, an environmental performance index is proposed to examine the environmental impacts of WDNs. Moreover, in order to evaluate the overall performance in regards to the costs, a value index in the system dynamics framework is proposed. Then, based on the developed framework, improvement strategies for a WDN are assessed by applying scenarios according to constraints and requirements of the network. The considered scenarios are as follows: (1) reducing per capita water demand of the WDN; (2) decreasing the average pressure in the WDN; (3) reducing the mean age of the system by its renewing; and (4) a combination of reducing the per capita water demand and average pressure in the WDN. The results indicate that the best solutions for increasing the value index in this network are: (a) to reduce the pressure of the pressure reducing valves (PRV) from 30 to 28 m; (b) to reduce the per capita water demand by the annual rate of 0.5% and 1% and decreasing the pressure of the PRV valves together. Therefore, it is shown how the developed algorithm is a purposeful approach for evaluating and improving the performance of WDNs based on the value index.

Environmental assessment of construction and renovation of water distribution networks considering uncertainty analysis

“…For WDNs equipped with pumping stations, the environmental impacts of the operation phase mostly depend on the pumping energy, which is influenced by several factors such as topography and the efficiency of the pumps (Sanjuan-delmás et al 2014) or even the energy mix. In addition, for gravity-driven water networks, operation impacts are mainly caused by pipe breaks, which have minor environmental effects compared with those derived from the construction stage (Hajibabaei, Nazif, and Sitzenfrei 2019). Therefore, the system boundaries defined in this study were focused on the different phases in the construction and renovation stages to provide more general detailed data for WDNs.…”

“…Figure 6 demonstrates that considering the different life spans for pipe materials can turn them into the options with the highest or lowest impacts. Several studies have been conducted based on LCA to identify the best or worst pipe materials (Piratla et al 2012;Du et al 2013;Vahidi et al 2016;Hajibabaei, Nazif, and Sitzenfrei 2019). However, it can be concluded from Figure 6 that considering several factors such as life span, design pressure, and diameter can significantly affect the environmental burdens of different pipe materials.…”

Application of the analytical hierarchy process for planning the rehabilitation of water distribution networks

“…Several researchers have studied different aspects of WDN rehabilitation including: (1) planning of rehabilitation, (2) strategies to improve rehabilitation practices (Hajibabaei, Nazif, & Sitzenfrei, 2019), (3) rehabilitation techniques and (4) factors influencing WDN rehabilitation. Due to the complexity of using multiple criteria to solve the rehabilitation problem and the lack of data, researchers have promoted the application of multicriteria decision making methods (MCDMs) as an effective decision support tool.…”

Dynamic edge betweenness centrality and optimal design of water distribution networks

“…Water distribution networks (WDNs) as pivotal urban infrastructures are comprised of various components interacting in a complex way [1]. Apart from the inherent complexity, major financial investments are required for the construction, operation, and renovation of WDNs.…”