Room for the River

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. With the dual objective of flood safety and landscape development, the program focussed on preventing high water levels, improving landscape quality of river areas and restoring ecological values. Researchers from Utrecht University evaluated the juridical-administrative approach of the project and its effects on biodiversity and sediment deposition. 

Illustration of a selection of measures taken in the Room for the River project
A selection of measures taken in the Room for the River project. Source: Straatsma et al. (2019), reprinted with permission

Biodiversity recovery

Biodiversity scores

River systems and deltas have the potential for high biodiversity, but human activities increasingly put them under pressure. Within the Rivercare project, Menno Straatsma, assistant professor of natural hazards and geocomputation, and colleagues estimated the effects of the measures taken in the Room for the River project on biodiversity. Using landscape-ecological maps from before and after the implementation of the measures plus extensive field observations from the National Database on Flora and Fauna, they calculated scores that describe biodiversity changes.

Recommendations for future interventions

The scores showed that biodiversity increased in 76-93% of the 179 floodplains examined along the rivers, underlining the effectiveness of the dual objective of the project. They particularly showed an increase in fast-spreading species, however many species had not yet returned despite the presence of suitable habitat. Menno Straatsma says, "Therefore, I urge project managers of future river interventions to better consider habitat requirements for endangered species, improve the connectivity of river corridors and invest in biodiversity monitoring".

Sedimentation in floodplains

Locally increased sediment trapping

Measures taken in the Room for the River project, such as the lowering or removal of embankments, floodplain lowering, and constructions of side channels, increased the supply of water and suspended sediments to the floodplains. These measures, together with more frequent floods due to climate change, locally increased the trapping efficiency of floodplains. However, higher flow velocities in the floodplains due to the Room for the River measures also reduced sediment settling.

No net impact

Unaltered floodplains are inundated less often because the measures cause an overall reduction in water levels, thereby decreasing sediment deposition in these unaltered floodplains. Marcel van der Perk, associate professor engaged in research on floodplains, further elucidates, "Recent modelling work shows that these effects combined result in a very small, almost negligible net increase of sedimentation in flood plains after the Room for the River project".

Photos of a floodplain of the IJssel river before and after the Room for the River project
Floodplain of the IJssel river before (left) and after (right) the Room for the River project. Credits: Rijkswaterstaat

Juridical-administrative approach

Integrated approach

The integrated approach adopted by the government is one of the factors that contributed to the smooth completion of the Room for the River program. In contrast to ‘sober and efficient’ measures like dikes, the innovative measures were developed in cooperation with local authorities thereby accounting for large scale river dynamics and long-term landscape development. This promoted flexibility during the planning and emphasized the utility and necessity of the project which increased public support and prevented lawsuits. In addition, the central government established a national project office, thereby providing professional guidance and support for local authorities in their decision-making and facilitating cooperation. The project office monitored whether the projects executed by the local authorities achieved their objectives on time and within the available budget. 

Coupling of objectives in the Room for the River project provided an opportunity to address multiple challenges

Frank Groothuijse, associate professor of environmental law, notes, “The coupling of objectives in the Room for the River project provided an opportunity to effectively address multiple challenges at the same time”. By integrating flood risk management with spatial planning, financial resources were made available to increase landscape quality parallel to flood safety. As a result, local authorities seized the opportunity to realize their own objectives within the Room for the River project, such as developing recreation and nature areas. This improved the cooperation between the central government and local authorities, as well as increased public support from an early stage of the project. Frank Groothuijse concludes, “The most important success factor of the Room for the River program was that the central government took responsibility for flood risk management at the river basin level in combination with improving spatial quality in close collaboration with the regional and local authorities and other stakeholders involved”.

More storylines about Room for the River

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Coastal forelands

With an interdisciplinary approach, researchers at the Water, Climate and Future Deltas hub explore the barriers and opportunities for integrated flood risk management in the Rhine-Meuse delta and other deltas worldwide. 

Global perspective
Future challenges
Interdisciplinary research group