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

Abstract

Urban pluvial flooding occurs when the capacity of sewer networks is surcharged due to large amounts runoff produced during intense rain events. Rapid urbanization processes and changes in climate increase these events frequency. Effective and sustainable approaches for the reduction in urban floods are necessary. Although several gray, green and hybrid measures have been studied, the influence of network structure on flood occurrence has not yet been systematically evaluated. This study focuses on evaluating how different structures of a single urban drainage network affect flood volumes and their associated damages. Furthermore, a cost–benefit analysis is used to determine the best network structure. As a case study, a sewer subnetwork in Dresden, Germany was selected. Scenarios corresponding to different layouts are developed and evaluated using event-wise hydrodynamic simulation. The results indicate that more meshed structures are associated with lower flood volumes and damage. Moreover, all analyzed scenarios were identified as cost-effective, i.e., the benefits in terms of flood damage reduction outweighed the costs related to pipe installation, operation and maintenance. However, a predominantly branched structure was identified as the best scenario. The present approach may provide a new cost-effective solution that can be integrated into the development of different mitigation strategies for flood management.

Identification of High-Impact Uncertainty Sources for Urban Flood Models in Hillside Peri-Urban Catchments

“…The implemented urban flood model is based on the EPA Storm Water Management Model (SWMM) 5.1 [28]. This model was frequently applied in the field of urban drainage modeling (e.g., [85][86][87]). The model combines two general model types.…”