ľ¹Ï¸£ÀûÓ°ÊÓ

Flood risk is expected to increase in the future. Sea level rise, more frequent peaks in river discharges and extreme weather events pose a challenge to decision makers dealing with flood risk management.

Like the Netherlands, Belgium, France and the United Kingdom are increasingly embracing the idea of integrated flood risk management. Nevertheless, with different physical conditions and political climates, they employ different strategies.

Coastal forelands are unprotected areas between the sea or estuary and a dike, and are common features in the Rhine-Meuse delta. Most forelands consist of a high-lying salt marsh alongside a dike with lower unvegetated mud flats lying in front.

Dike constructions protect the Rhine-Meuse delta against river flooding and storm surges coming from the North-Sea. Dike failure is not always related to flooding but can also result from subsurface and groundwater mechanisms.

Room for the River is a nationwide program adopted by the Dutch government in 2005-2015 as a response to severe floods in 1993 and 1995. Instead of the local implementation of flood protection measures, the project applied a system approach by implementing more than 30 measures along the Rhine, Meuse, and their distributary rivers.

Integrated solutions, combining flood safety with other societal needs, are a response to the need for more sustainable and flexible flood risk management.

Integrated flood risk management requires a change in mindset to step out of the traditional way of thinking about flood protection. Moreover, it enhances the complexity of management approaches and therefore multiple barriers are currently encountered during the implementation.

Sea level rise, land subsidence and more frequent extreme rainfall and storm events enhance the risk of flooding in deltas. Flood risk management is required to maintain the population’s safety and to prevent and compensate for economic damage.

Contact persons of the storyline 'Sinking deltas' of the Water, Climate and Future Deltas hub at Utrecht ľ¹Ï¸£ÀûÓ°ÊÓ, a platform for scientists and external stakeholders to jointly work on ensuring the sustainability of our world’s deltas.

The unexplored rates of land subsidence, its lack of acknowledgement in policy agendas, the divergent interests and the unknown socio-economic consequences of potential management strategies emphasize the need for future scientific attention, societal discussions, and an integrated view on land subsidence.

The Ciliwung delta, for the largest part occupied by Indonesia's capital city Jakarta, faces rapid subsidence caused by excessive groundwater extraction and construction load.

The Mekong delta in Vietnam is experiencing high rates of land subsidence due to excessive groundwater extraction, driven by rapid urbanization, land-use change, and intensification of agricultural and economic activities.

The Rhine-Meuse delta in the Netherlands is subsiding due to the drainage of agricultural soils. This has been causing an increase in economic damage, flood risk and greenhouse gas emissions.

The Water, Climate and Future Deltas hub engages in research on land subsidence in deltas worldwide, especially in the Rhine-Meuse, Mekong, and Ciliwung deltas.

Land subsidence is becoming a visible and urgent problem in deltas worldwide, which is compounded by sea level rise and a reduction in sediment supply.

Contact persons of the storyline 'Sediments matter' of the Water, Climate and Future Deltas hub at Utrecht ľ¹Ï¸£ÀûÓ°ÊÓ, a platform for scientists and external stakeholders to jointly work on ensuring the sustainability of our world’s deltas.

The urgent need for sediment management strategies and upscaling to larger-scale projects to prevent deltas from drowning requires future scientific attention.

Sedimentation enhancing strategies are crucial to keep deltas from drowning and their populations safe. Often strategies are implemented on a local scale, but it remains unclear whether they can be upscaled and applied in deltas more broadly.

Strategies that retain sediment, also called sedimentation enhancing strategies, aim to restore and facilitate land-building processes in deltas.

Sand nourishments on beaches and ebb-tidal deltas are examples of strategies that relocate sediment with the aim of accumulating sediment along the coast to mitigate flooding.