Rainfall floods: tackling the rising risk of critical infrastructure failure

Critical infrastructure failures resulting from rainfall-induced floods pose substantial risks to society, public health, economies, and the environment. Recent heavy flooding in Europe proves that rainfall is able to shut down cities leading to enormous damage and costs. A new Urban Insight report from Sweco “Expect the Unexpected: Floods and Critical Infrastructure” delves into cities’ preparedness to withstand rainfall-induced floods’ impact on critical infrastructure. It explores how cities can prepare for unforeseen events and proactively plan to enhance both urban and critical infrastructure resilience.

Studies show more intense and frequent heavy precipitation will hit European cities. This emphasises the need for comprehensive risk assessment and management, also in relation to critical infrastructure. The European Union’s new Critical Entities Resilience Directive (CER) mandates measures to ensure uninterrupted essential services across 11 critical sectors. Sweco explores the vulnerability of critical infrastructure to rainfall-induced floods in European cities.

To investigate vulnerabilities, impact, and mitigation strategies, the report employed a multifaceted approach. First, policy analysis: An examination of climate adaptation policies and water management plans from 26 European cities provided a foundation for understanding the existing framework for managing climate risks. Second, stakeholder interviews: Complementing policy analysis, interviews were conducted with city representatives. These insights offered practical perspectives on critical infrastructure vulnerability and the specific challenges cities face.

Key findings

This study has shown that cities were not designed for our changing climate. In addition, factors such as urbanisation, outdated infrastructure, and geographical location significantly influence exposure to climate risks. Planning for these rain events is an extremely complex and demanding task for local governments and their partners. It is crucial to study critical infrastructure both on the district level and asset level.

Sweco’s research finds that local governments predominantly prioritise technical infrastructure (e.g. transport and electricity systems) over social infrastructure like hospitals, nurseries, and elderly care facilities. Surprisingly, critical elements like banks, data centers, and crisis centers are often overlooked yet they are the backbone of our financial system. The study also highlights the often-overlooked psychological impacts of infrastructure failures, including stress and fear among affected populations.

Infrastructure systems are interdependent, so failure of one system can cause other systems to fail as well. These cascade effects can have unexpected and serious societal consequences. With Sweco’s combination of policy analysis and stakeholder input, we formulated these actionable recommendations:

The way forward

At Sweco, we know from our projects that building resilience is an iterative process and requires a holistic, interdisciplinary approach. The city is in constant flux, so hazards will also change. In addition, our understanding of climate change is evolving – all good reasons to assess risks and update measures at regular intervals.

Policymakers at city level and managers of critical infrastructure must collaborate to assess and mitigate climate risk comprehensively. Each iteration in this process will produce more data and insight to better support investment decisions in resilient critical infrastructure. Starting the analysis is essential. In this Urban Insight report, we look at seven key steps that need to be taken towards a more resilient future.