ľ�ϸ���Ӱ��

By 2030, 147 million people and €650 billion in urban property worldwide could be damaged by flooding, according to the newly developed World Resources Institute’s flood risk tool. The tool, , also finds that investing in flood protection infrastructure now can decrease the impact of floods in the future. Marc Bierkens, professor of hydrology at Utrecht ľ�ϸ���Ӱ��, contributed to the tool with the global hydrological model developed by his research group.

Flooding is a serious and dangerous global risk, impacting people, property, livelihoods, and economies. Climate change is expected to intensify flooding in the coming decades, while economic growth and urbanisation place more people and property in flood-prone areas. “Economic damages from floods are already formidable under the current climate, and will grow tremendously in the future as a result of climate change and socioeconomic development,” says Utrecht ľ�ϸ���Ӱ��’s hydrology professor Marc Bierkens.

Providing the necessary data

Despite these dangers, flood risks are often underestimated and poorly managed due to lack of transparent, accurate data on current levels of flood protection, both in developing and developed countries. The Aqueduct Floods tool can help fill in this critical information gap. It provides data to analyse flood risks and understand the costs and benefits of interventions, such as dikes, to reduce flood risk. The tool measures riverine and coastal flood risks under current baseline conditions and future projections in 2030, 2050 and 2080. It examines the extent to which populations, GDP and urban property will be impacted by flooding. Marc Bierkens and his team provided the global hydrological simulations needed to assess current and future riverine flood hazard.

Drivers of flooding

Climate change, socioeconomic growth, and land subsidence are drivers of worldwide flooding. The Aqueduct Floods tool analyses the effect of these and other drivers. It finds that people living in countries with coastlines will be more exposed to coastal floods by 2030 than today. Ten countries account for 84% of the population that will be newly exposed to coastal flooding by 2030: Bangladesh, Vietnam, India, Indonesia, China, Nigeria, the Philippines, Myanmar, Egypt and the Netherlands. Caused by the overexploitation of groundwater, land subsidence in coastal cities puts an additional 2 million people at risk of coastal flooding by 2030.

The Dutch case

“The Netherlands is a special case in this study,” says Bierkens. “The Netherlands has the highest protection level in the world for both coastal and fluvial floods. Also, our Delta plan will likely assure that we stay protected in the future as well. The tool is therefore mostly meant for the many areas in the world where no flood protection is in place and where one has to start thinking about investments in protective measures under future climate change”.

Flood protection pays off

For these countries, the tool offers comprehensive cost-benefit analysis to evaluate the value of dike flood protection strategies. Investing in hard infrastructure like levees and dikes, protecting and restoring natural infrastructure like coastal mangroves and forests in watersheds around cities, creating insurance and development policies that mitigate flooding and improving sustainable groundwater management are all vital. Such tools can help decision-makers anticipate flood risk and damage before it happens and put the right protections in place. It also enables companies, governments, and other stakeholders to make informed investments in climate adaptation strategies.

Consortium of data partners

The tool was created by a consortium of data partners, including Utrecht ľ�ϸ���Ӱ��, World Resources Institute, Deltares, Vrije Universiteit Amsterdam’s Institute for Environmental Studies, and PBL Netherlands Environmental Assessment Agency, with funding support from the Dutch Ministry of Infrastructure and Water Management and the World Bank.