Vulnerability Analysis of Urban Drainage Systems: Tree vs. Loop Networks

Abstract

Vulnerability analysis of urban drainage networks plays an important role in urban flood management. This study analyzes and compares the vulnerability of tree and loop systems under various rainfall events to structural failure represented by pipe blockage. Different pipe blockage scenarios, in which one of the pipes in an urban drainage network is assumed to be blocked individually, are constructed and their impacts on the network are simulated under different storm events. Furthermore, a vulnerability index is defined to measure the vulnerability of the drainage systems before and after the implementation of adaptation measures. The results obtained indicate that the tree systems have a relatively larger proportion of critical hydraulic pipes than the loop systems, thus the vulnerability of tree systems is substantially greater than that of the loop systems. Furthermore, the vulnerability index of tree systems is reduced after they are converted into a loop system with the implementation of adaptation measures. This paper provides an insight into the differences in the vulnerability of tree and loop systems, and provides more evidence for development of adaptation measures (e.g., tanks) to reduce urban flooding.

Potentialities of Complex Network Theory Tools for Urban Drainage Networks Analysis

“…Also vulnerability assessment for urban water systems is a very important topic, generally defined to analyze the effects of failures (Zhang et al., 2017). Resilience, instead, is a concept that integrates reliability of the network when subjected to the usual loading and minimization of malfunctions in case of unusual situations.…”

Determination of Optimal Meshness of Sewer Network Based on a Cost—Benefit Analysis

“…In this latter case, the available storage is typically increased by constructing stormwater tanks or increasing the dimensions of the existing infrastructure, for example by installing pipes with bigger diameters Although these are efficient solutions for reducing pluvial flood risks, recent studies have also suggested that the physical arrangement, i.e., the layout, of the sewer network may play an important role in the occurrence and magnitude of pluvial flood events. Zhang et al [10] suggested that sewer networks with a more meshed structure are less vulnerable to structural failures, e.g., blockages, and are associated with lower flooding volumes than systems with a tree-like structure. Reyes-Silva et al [11] analyzed the influence of network structure, quantified in terms of a Meshness coefficient, on the occurrence and magnitude of node flooding using eight different sewer networks.…”

Assessing Redundancy in Stormwater Structures Under Hydraulic Design

“…In this context, examples of studies are rare. Zhang et al studied the impact of branched and looped systems on the vulnerability of urban drainage systems based on blockage scenarios (structural failures) [22]. Their results demonstrated that looped systems possessed a lesser proportion of critical elements compared to their branched counterparts.…”