Shortest-Path-Based Two-Phase Design Model for Hydraulically Efficient Water Distribution Network: Preparing for Extreme Changes in Water Availability

Abstract

Environmental issues can cause changes in source water availability in water distribution networks (WDNs). Thus, an efficient connection between the source and consumers is important for securing water serviceability, which can generally be achieved by minimizing energy losses. In this study, a novel two-phase design (TPD) model is proposed to design an energy-efficient WDN by maximizing a hydraulic geodesic index (HGI), which is the weighted shortest path from the source to the demand node. Before applying the TPD model for WDN design, a correlation analysis between the system HGI, hydraulic performance, and graph theory indices is conducted using 33 J-City networks to verify the proposed HGI. Next, the TPD model is used to determine the optimal layout of the grid network (Phase I). Based on this layout, the optimal diameter set is identified in Phase II. The TPD is thereafter compared with the traditional single-phase design (SPD) model, which determines the optimal layout and diameter simultaneously, and a least-cost model for each phase in the grid network layout and pipe-sizing problem. The correlation analysis clearly indicates that the system HGI with the weighted graph theory successfully determines the hydraulic performance without any hydraulic analysis. Furthermore, TPD is advantageous for designing energy-efficient, hydraulically and structurally sustainable, and resilient networks, as compared to SPD and the least-cost model. The TPD model is expected to provide a better opportunity to prepare for extreme water availability changes by enhancing the hydraulic performance and efficiency through a better connection between the source and nodes.

Designing Isolation Valve System to Prevent Unexpected Water Quality Incident

“…In both optimization techniques, FDC is incorporated as a constraint to address the risk of water quality incidents, while the single-objective model includes the number of valves installed as an additional constraint. Furthermore, the Hydraulic Geodesic Index (HGI) [30], robustness index [31], and modified resilience index (MRI) [32] were employed to assess the performance of the proposed approach. This section provides a detailed description of potential water quality risks, optimization models, and performance evaluation metrics (Figure 1).…”

“…In the case of WDNs, which exhibit a geometric shape similar to graphs, graph theory has been frequently employed for analyzing nodal connectivity. In this study, to examine the characteristics of design alternatives with or without considering FDC, we utilized the HGI proposed by Lee and Jung [30], which is based on graph theory. HGI quantifies the connectivity between the water source and each demand node, emphasizing the connectivity among various nodes rather than the overall connectivity.…”

“…In this study, various performance indicators were considered to compare the performance of the traditional design with that of the proposed design. Firstly, as isolation results in disconnection, we evaluated a surrogate measure of connectivity, specifically the HGI [30]. Comparing HGI allows us to assess whether all demand nodes remain connected to the water source or not.…”

Seismic Performance Assessment of Water Distribution Systems Based on Multi-Indexed Nodal Importance

“…This study takes the length of pipelines as the weight of network links, which is similar to the approach by Torres et al [41]. Several studies have explored the applications of weighted and unweighted geometric network models of WDS [11,22,38,[42][43][44]. The influence of other weighting approaches on the values of index I31 is worth exploring further research.…”