Room for the River — Netherlands National Flood-Conveyance Programme

After near-catastrophic Rhine and Meuse floods forced mass evacuations in the Netherlands in the early-to-mid 1990s, Dutch authorities shifted flood-safety strategy away from ever-higher dikes toward giving rivers more physical room. The Room for the River programme was formally adopted in 2006, covering the Rhine's Dutch branches — the IJssel, Waal, Nederrijn and Lek.

Increase river discharge capacity and lower flood risk by widening floodplains and relocating dikes, rather than raising them further.

Between 2006 and 2019, national and regional authorities completed 34 measures for a combined EUR 2.3 billion: relocating dikes further from the riverbank, lowering floodplains, reducing groyne heights, deepening side channels, and depoldering land. The largest single measure, the Noordwaard polder near the Biesbosch, cost about EUR 300 million and converted roughly half of its 4,450 hectares into a controlled flood area, while ring levees protect the remaining 700 hectares of farmland; the number of farmers working the polder fell from 25 to 8 and households from 60 to 22, with relocation and compensation funded by the state.

Rijkswaterstaat reports that additional discharge capacity created near Gorinchem — where a 2 km stretch of levee was lowered by about 3 metres — is expected to lower Rhine water levels there by roughly 30 cm during high-flow events, part of a design target of safely conveying 16,000 m3/s. The programme is credited by Rijkswaterstaat and the OECD with improving flood safety for roughly 4 million people along these rivers.

Systematic, site-by-site before/after monitoring across all 34 projects is not published — the most specific quantified results (Noordwaard, Gorinchem) are single-site figures, and the discharge-capacity target is partly a modelled design standard rather than an observed flood outcome.