Flood risks

Hundreds of millions of people around the world are at risk of flooding from the sea, from rivers or as a result of extreme rainfall. Every year, there are thousands of casualties and extensive damage. Population growth, economic development and climate change mean these numbers will continue to increase in the future.

Deltares is committed to making countries and regions less vulnerable to flooding by acquiring more knowledge in the field of protection, dike failure mechanisms, better quantification of risks, developing sustainable and effective solutions (such as flood risk management landscapes) and developing forecasting and warning systems. In this way, we can contribute to making the world safer for floods at an acceptable cost.

We can never completely prevent floods, but we can focus on making them more manageable. The challenges are enormous, but if we go about this in the right way now, the problems will remain manageable and we can prepare in the best way possible.

Jaap Kwadijk

Flood risk strategies

More and more countries need to quantify, and limit flood risks. Deltares assists authorities throughout the world to better understand the risks of floods and to develop strategies to cope with the global increase in flood risk.

We support a pro-active approach to integrated flood risk management, as advocated in the Sendai Framework for Disaster Risk Reduction. Deltares Flood Risk Strategies aim to improve concepts, methods and tools in three fields:

• Flood risk assessment;
• Urban flood management and critical infrastructure;
• Flood risk management: design and appraisal of strategies.

Flood risk assessment

Deltares maps out flood risks by conducting integrated risk analyses. We analyse the probability of high water levels and floods and assess the potential impacts of flooding, including loss of life, economic losses and environmental impacts.

Risk analysis provides insight into the vulnerability of specific areas, which is important for planning of spatial developments. Deltares develops and applies coherent sets of methods and tools for risk analysis on various scales, including the development of meaningful indicators, metrics and maps.

Urban flood management and critical infrastructure

Urban areas with critical infrastructures such as utility networks, roads and railways are particularly vulnerable to flooding. Critical infrastructure is not only at risk of flooding but of cascading effects as well. Deltares develops collaborative modelling tools to enhance stakeholder involvement in tracking down these risks and develop strategies for risk reduction in response.

Development of strategies for flood risk management

Strategies to be developed should comprise a well-balanced mix of both structural and non-structural measures, including measures which can be implemented on the short term. In planning for flood risk management there is a need to decide what level of flood risk is acceptable, to decide how safe is safe enough.

Risk informed decision-making looks for a ‘proportionate’ response to risk as well as a transparent process of estimating the risk and assessing the impacts of measures. To support this process, Deltares develops and applies (interactive) methods and tools for (participatory) design and appraisal of flood risk management strategies, such as planning kits and dashboards.

Flood defences and flood risk management

At Deltares, we work to protect the Netherlands against flooding in collaboration with various parties such as water boards, the Department for Infrastructure and the Environment, and engineering firms. Deltares is part of what is known as the “Golden Triangle” (government, business, knowledge). We develop knowledge that is useful for governments and businesses. Our focus is on making flood defences flexible and resilient and integrating spatial developments.

With the new Environment Act, we see opportunities for optimisation in the design and assessment of flood defences. We help by developing targeted knowledge and investigating failure mechanisms and failure paths in order to better assess and reduce the risk of flooding.

Flood risk forecasting and warning

Flood risk can never be completely eliminated, but it can be reduced by timely warnings. Flood prediction systems play a crucial role in this by combining current weather conditions with knowledge of the water system in near real time. Deltares provides the necessary software, knowledge and experience to make these systems operational, contributing to greater flood safety.

These systems are often used by government agencies such as Rijkswaterstaat and the National Weather Service. We develop these systems in co-creation with the users, combining knowledge of the water system with operational experience. In addition to supplying systems, Deltares also provides forecasts for organisations that do not operate their own systems but need to make decisions based on these forecasts.

Mapping river floods worldwide

River flooding will affect significantly more people and cause more damage by 2030 due to climate change and socio-economic developments. Currently, 21 million people are affected annually and the loss in GDP amounts to $96 billion worldwide. These figures are expected to rise to 54 million people and $521 billion in GDP per year by 2030. The “Aqueduct Global Flood Risk Analyzer”, developed by the World Resources Institute (WRI) and four Dutch organisations, provides insight into the consequences of river flooding in terms of GDP loss, affected population and damage in cities.

The tool, with a major contribution from Deltares, makes complex data accessible to non-scientists and helps policymakers in the public and private sectors to take timely measures against catastrophic damage. The Analyzer shows the risks per country or area and offers a glimpse into the future. In addition to river flooding, coastal flood risks will also be included in the future, as well as the feasibility and effectiveness of measures such as dykes and water storage systems.

Flood-resilient landscapes

Flood-resilient landscapes is an initiative by Deltares that responds to the increasing pressure on available space in the Netherlands. The concept focuses on combining different social values and developments to achieve optimal spatial planning. By focusing on the value of the area, water safety measures can be linked to other spatial and social challenges, leading to a more resilient system and greater support for water safety.

The research into flood-resilient landscapes is being conducted in collaboration with government bodies, knowledge institutions and private parties. Concrete case studies and the application of the Vision in Design methodology are being used to develop building blocks for the medium and long term.

This approach provides policymakers with tools for integrating water safety measures into broader regional transitions and contributes to a future-proof design for the Netherlands.