As Alderwoman Van Huffelen explained: 'This underground water storage is one of the innovative projects that allow Rotterdam to serve as a model to other delta cities. Preparing for the consequences of climate change enables us to ensure that the city will remain safe, accessible and attractive in future. This will benefit both the people who live and work here, and the businesses and corporations established in the area.'

The underground car park offers also a solution for the prevention of (future) flooding in Rotterdam city centre. Extreme rainfall causes flooding in the centre sooner because there is too little surface water there compared to ‘hard’ surfaces, such as streets and buildings. As a result, the streets located on a lower level become flooded and cellars submerged. To solve this a reservoir was built underneath the entrance to the car park, to collect no less than 10 million litres of water when there is heavy rainfall. As soon as the sewer system threatens to overflow, the hatch of the underground water reservoir is opened. Within half an hour, the reservoir - which measures 60 by 35 metres - fills up at enormous force with 10 million litres of water. When the downpour ends and there is space again in the sewer system, the water in the reservoir is pumped into the sewer. The cars parked underground are not affected by the water because the reservoir is completely closed off from the underground car park.Without the storage facility, the city would experience an average of ten annual overflow events, causing the water in the moats to be mixed with untreated sewage, leading to odour nuisance and massive fish mortality. This will significantly improve the water quality in the city moats.

The underground water storage facility is necessary to prevent the streets in the centre of Rotterdam from flooding during extreme rainstorms. There is not enough room in the densely built-up centre of Rotterdam to dig additional ditches or moats. However, these double purposes of parking cars and retaining excess water will always remain separate. Creating a car park that doubles as a water storage facility helps to optimize the use of the city's scarce space.