Multi-Objective Optimization for Urban Drainage or Sewer Networks Rehabilitation through Pipes Substitution and Storage Tanks Installation

Abstract

Drainage networks are civil constructions which do not generally attract the attention of decision-makers. However, they are of crucial importance for cities; this can be seen when a city faces floods resulting in extensive and expensive damage. The increase of rain intensity due to climate change may cause deficiencies in drainage networks built for certain defined flows which are incapable of coping with sudden increases, leading to floods. This problem can be solved using different strategies; one is the adaptation of the network through rehabilitation. A way to adapt the traditional network approach consists of substituting some pipes for others with greater diameters. More recently, the installation of storm tanks makes it possible to temporarily store excess water. Either of these solutions can be expensive, and an economic analysis must be done. Recent studies have related flooding with damage costs. In this work, a novel solution combining both approaches (pipes and tanks) is studied. A multi-objective optimization algorithm based on the NSGA-II is proposed for the rehabilitation of urban drainage networks through the substitution of pipes and the installation of storage tanks. Installation costs will be offset by damage costs associated with flooding. As a result, a set of optimal solutions that can be implemented based on the objectives to be achieved by municipalities or decisions makers. The methodology is finally applied to a real network located in the city of Bogotá, Colombia.

Multi-Objective Optimization of Drainage Networks for Flood Control in Urban Area Due to Climate Change

“…Finally, another type of DV is the head loss coefficient introduced in certain network pipes. The use of hydraulic controls has been mentioned in previous works as a tool to limit the flow of water [10] [17] retaining the upstream flow, which causes the water concentration time below to be smaller, reducing flooding. In this work the inclusion of a minor head loss that is installed in the initial part of the pipes that come out of STs will be used as hydraulic control.…”

An Analysis of Stormwater Management Variants in Urban Catchments

“…It is also worth emphasizing that there are often situations in which conduits are not completely used in terms of hydraulics and have significant unused capacity above the rainwater table that can be included in the retention volume of the drainage system [37]. This fact is of colossal significance in the aspect of slowing down rainwater runoff to receivers and limiting their negative impact, but it is also very important for economic reasons [38,39].…”

Decision Criteria for the Development of Stormwater Management Systems in Poland

“…Their location in appropriate places is an important way of adapting urban catchments to expected climate changes [21]. Sustainable stormwater management systems [22] can be used both in existing and newly-constructed infrastructures, although the possibilities of applying individual devices, including nature-based solutions, are limited, and the effectiveness of operation is dependent on a range of factors [23][24][25]. Potential restrictions are mainly related to the characteristics of the drained catchment and the area within which the stormwater management system is to be located.…”