Evolution of Flood Defense Strategies: Toward Nature-Based Solutions

Abstract

Flood defense strategies have evolved from hard-engineered systems to nature-based solutions that advocate for sustainability to meet today’s environmental, social, and economic goals. This paper aims to analyze the historical progression and evolutionary trends in flood control strategies that have led to nature-based solutions. An evaluative literature review was conducted to narrate the evolution of nature-based flood management approaches for different flood types, river floods, coastal floods, and stormwater run-offs. The analysis reflected three evolutionary trends: the transformation of hard measures to soft measures; secondly, the increase in society’s attention to ecosystems and their services; and, finally, divergence from single-function solutions to multi-function solutions. However, continuous monitoring and evaluation of the previous projects and adapting to the lessons learned are the key to progress towards sustainable flood management strategies and their societal acceptance.

Rethinking Estuary Urbanism—Preparing Australian Estuary Cities for Changes to Come in the Climate and Biodiversity Emergency

“…Simultaneously, the area serves as space to retain, treat, and store water, rainwater and runoff while offering recreational, cultural, and environmental opportunities. Design strategies combine Nature based Solutions (NbS) [76][77][78][79][80], Water Sensitive Urban Design (WSUD) [74,[81][82][83] and Alternative (or Nature-based) Flood Defence [81,[84][85][86] to generate bluegreen corridors and urban spaces acting as buffers zones to protect the urban environment and enhance natural water systems. This helps manage runoff, reduce urban heat island effects, and guarantee urban ecological connectivity to foster biodiverse corridors for flora and fauna since major environmental pressures in Newcastle LGA include the fragmentation of fauna habitats with limited integration of these in planning locally [7].…”

Nature-Based Solutions for Disaster Reduction and Improving Ecosystem Services in the Hutoubi Watershed, Taiwan

“…The Netherlands's Room for the River program combines traditional measures with NbS, such as creating floodplains and wetlands to manage flood risk [4,5]. These examples illustrate the importance of integrating NbS into river management strategies, promoting sustainable and resilient systems that benefit humans and the environment [6]. NbS offers several advantages, such as enhancing biodiversity, improving water quality, and mitigating the impacts of floods and droughts [1,7].…”

The Role of Green Infrastructure in Pluvial Flood Management and the Legislation Surrounding It: A Case Study in Bristol, UK

“…Flooding in the UK has increased dramatically since 1884 and is now experiencing the highest frequency recorded costing the economy £1.6 billion in 2015/2016 [7]. Hard engineering for flood defence including drains, sewer systems, and gutters have been commonplace in cities since their inception, as a method of quickly draining rainwater, with the intention of providing enough capacity to prevent pluvial flooding in extreme weather conditions [8]. However, the increasing scale of urbanisation, higher annual rainfall, and climate change have all put pressure onto these systems, requiring more protection and swelling the costs of operating, designing, and maintenance [8].…”

“…The past decade has seen various studies investigate the most effective NbS for urban pluvial flood risk management [8,14,18,19]. These studies have quantified both the benefits of various methods of NbS and identified the most effective techniques for a range of situations in the urban environment.…”

“…Due to climate change drastically increasing the amount of smaller scale flooding events that are seen from 1-15 years in comparison to large scale events, this information provides backing for NbS being an effective tool and gives creditability to further implementation in urban environments in the UK [23]. Due to the increasingly adverse and common nature of pluvial flood risk throughout the UK, a critical review of multi-scale legislations and policies regarding NbS for flood management will be undertaken, as well as an evaluation of current systems in place for a case study of choice, in order to provide a reliable analysis of how the threat of pluvial flood management is handled and regarded in UK cities [8,14,15].…”