Benthemplein Water Square — Rotterdam's First Full-Scale Multifunctional Stormwater Plaza (Netherlands)

Benthemplein in Rotterdam is the Netherlands' first full-scale 'water square': a public square (sports courts, amphitheatre) designed to store stormwater in three basins. Opened on 4 December 2013, it was designed by De Urbanisten for the City of Rotterdam with the water board.
Two shallow basins fill with every rainfall; a deeper basin fills only during sustained heavy rain. Together the basins can hold about 1,700 m³ of rainwater, which is then drained to the surface water or infiltrated rather than overloading the sewer. The cost was about €4.5 million (€4 million budget cited by another source including pipes, pumps, engineering).
Caveats: the sources reviewed (WEF Stormwater, De Urbanisten, PublicSpace) are design and project descriptions; no post-construction monitoring of actual retained volumes, avoided flood damage or biodiversity was found, so evidence for outcomes is design-based. No carbon or biodiversity claims are made. Strength is in governance and replicability: the water-square concept has been reused in other Dutch and international cities.

Read the full analysis: https://stormwater.wef.org/2014/03/first-full-scale-water-square-opens-rotterdam/