When it rains in New York City, the grounds of the South Jamaica Houses housing project start to flood. Sometimes, the water doesn’t drain for days or weeks, making basic mobility a challenge for the complex’s 3,000 residents. Soon, however, construction crews will sink a basketball court several feet into the development’s ground with tiers of benches on either side. During major rainstorms, this sunken stadium will act as an impromptu reservoir for water that would otherwise flood housing.

Initially planned by Ramboll under contracts with New York City Department of Environmental Protection (NYCDEP), this project will be able to hold 200,000 gallons (757,000 litres) of water before it overflows. It will release water to the sewer system slowly, preventing it from backing up as it does today. The project is funded by NYCDEP and will be used as a model for other similar projects within the city’s ‘cloudburst program’, which has been established with inspiration from Copenhagen and Ramboll. In 2023, the Mayor of New York, Eric Adams, expanded the cloudburst program by raising an additional $400 million in capital funds from municipal and federal funding.

A socio-economic analysis from Ramboll and the NGO Rebuild By Design shows that New York City can expect a two-to-one return on its investments in multifunctional blue-green infrastructure protecting communities against cloudburst. This return is mainly due to co-benefits driven by blue-green infrastructure typologies.