Room for the River Waal – protecting the city of Nijmegen

At Nijmegen, the Waal — the Netherlands' largest river — narrows and bends sharply, historically causing flooding of the city's low-lying historic centre. After severe floods in 1993 and 1995, and with climate change expected to increase peak river flows, Nijmegen and the Dutch national 'Room for the River' programme (approved 2007) set out to widen the river's course rather than continue to raise dikes.

The project's objective was to improve flood protection for the city of Nijmegen and the village of Lent by creating more space for the river to carry high flows, while also creating recreational and natural space.

Between 2012 and 2016, the existing dike protecting Lent was moved 350 m inland and a new 150-200 m wide, 3 km long ancillary river channel was dug parallel to the original course. Barriers separate the two channels so that, in normal conditions, water flows only through the main river; during high flows, part of it is routed through the new channel. The project also created a new island, now an urban river park, with new and extended bridges providing access.

The project cost an estimated €351 million, mostly funded from the national budget. Its completion in 2016 achieved a 35 cm reduction in river water levels at Nijmegen, exceeding the initial 27 cm target; during high flows, roughly one-third of total discharge is now carried by the ancillary channel. A social cost-benefit analysis found the project generated more than $295 million in net positive economic effect, alongside improved natural landscape and new recreational space in the city.

Climate-ADAPT identifies national government coordination and funding, spread across multiple measures at different locations under the wider Room for the River programme, and broad stakeholder and community involvement, as the main success factors. Budget limits were partly addressed with additional funding from provinces, water boards and municipalities; land expropriation and compensation for periodic flooding of land used in the works were necessary limiting factors to manage.