Governance Strategies for Improving Flood Resilience in the Face of Climate Change

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.

Section: Introductionmentioning

confidence: 99%

“…As stated by Driessen et al [10], any strategy which seeks to reduce floods has some costs. Ugarelli and Di Federico [17] presented a cost-based methodology for drainage networks service level upgrading.…”

Section: Introductionmentioning

confidence: 99%

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

Ngamalieu-Nengoue

Martínez-Solano

Iglesias-Rey

et al. 2019

“…It is imperative to dedicate continued research to addressing data deficiencies so the role of flood damage assessments as decision-support mechanisms is strengthened. Flood damage assessments are also key for raising awareness of flood risks and closing the gap between perceived and actual risks [55]. Flood damage assessment therefore plays the important role of increasing awareness of flood risks prior to disasters so societies can be better prepared to reduce future flood risks.…”

Section: Looking Towards the Futurementioning

confidence: 99%

Understanding the Costs of Inaction–An Assessment of Pluvial Flood Damages in Two European Cities

Nicklin

Leicher²,

Dieperink

et al. 2019

Today, over 50% of the global population lives near water. Due to population growth, ongoing economic development, and extreme weather events, urban areas are growing more susceptible to flood risks, and the costs of inaction of failing to manage flood risks are high. Research into the benefits of pluvial flood-risk management is needed to spread awareness and motivate investments in pluvial flood-risk reduction. So far, such research is lacking. This research therefore assesses pluvial flood damage from a single 60mm/1-hour rainfall event in the cities of Rotterdam and Leicester using 3Di flood modelling and the flood damage estimation tool (waterschadeschatter; WSS). The results demonstrate that potential pluvial flood damages exceed €10 million in each city. From this research, inhabitants and authorities of Leicester and Rotterdam can learn that preparing for upcoming pluvial floods can save millions of euros resulting from future damages. The application of these tools also makes clear that data availability is a highly relevant bottleneck to the pluvial flood damage assessment process. By addressing data shortages, flood damage estimates can be strengthened, which improves decision support and enhances the chance actions are taken in reducing pluvial flood risks.

“…The complex functions of urban areas need to be considered in the design process of urban stormwater systems, increasing resilience to climate change and enhancing attraction and social inclusion of urban environments [1] especially regarding flood management. Land use changes, urbanisation growth and climate change effects can potentialise the complexity of interactions between cities and urban floods [2]. human development is yet to be properly addressed.…”

Section: Introductionmentioning

confidence: 99%

A Framework to Evaluate Urban Flood Resilience of Design Alternatives for Flood Defence Considering Future Adverse Scenarios

Rezende

Miranda

Haddad

et al. 2019

In urbanized plains that are subject to flooding, the socioeconomic aspects, climate characteristics, built environment, and riverine processes exhibit bi-univocal relationships with the flood formation itself, creating a pattern of development without a predefined equilibrium state. The complexity of processes involved in flood management and the need for a comparative assessment method to hierarchise different design alternatives or planning scenarios requires practical and quantitative methods for urban diagnoses, including flood risk and resilience aspects. This paper proposes an alternative pathway to evaluate design alternatives for urban flood mitigation, assessing resilience in quantitative terms. In this way, a methodological framework is presented suppress to evaluate flood resilience in urban watersheds planning, through the application of the Urban Flood Resilience Index (UFRI) and Future Scenarios Criteria (FSC). A case study illustrates the method using an urban watershed in Rio de Janeiro/Brazil. This study considered two possible design alternatives for flood control, with concentrated and distributed measures. The resilience mapping using the UFRI showed that the adoption of distributed measures could increase the areas classified as showing very high resilience by 41%, while very low resilience areas would be reduced by 87%. The FSC is able to present the integrated results of resilience variation from present and future conditions, considering, for example, climate change effects or unplanned urbanisation scenarios. The framework is able to perform comparisons between alternatives, showing the advantages associated with adopting distributed measures over the watershed, which reflected in a resilience value that was 24% higher when compared to the results obtained for the concentrated solutions scenario.