Frequently Asked Questions


What is the RainGain project about?

The RainGain project aims to obtain high-resolution rainfall observations at urban scale, and to use them to analyse and predict urban pluvial floods.  Rainfall and flood data are used to improve urban water management and flood protection practices such as early warning systems and optimised, real-time storage basin operation. Four different weather radars are currently tested in Leuven, London, Paris and Rotterdam. Two dual-polarised X-band radar have been installed in the latter two sites.

What are the features and benefits of X-band dual-polarised radars?

The dual-polarised X-band radars tested by RainGain operate in a way which allows rainfall measurements to be made at higher temporal and spatial resolutions (1 min / 100 m) than are tipically produced by surveillance radars operated by meteorological services (usually 5 min / 1 km). The weight and cost of X-band radars are lower, which enables decentralized monitoring of rainfall.

Why are high-resolution rainfall measurements needed?

Temporal and spatial fine-scale rainfall observations are appropriate to water management in urban areas. Indeed urban floods can be caused by very local but intense rainfall that develop and move fast. In a very short time lapse these storms and can lead to intense rainfall water run-off that need to be quickly evacuated through the sewer network. High-resolution radar data can be used to better understand storm and flood episodes in urban areas, and therefore to make the sewer systems more resilient to these events. At the same time these data are used to obtain accurate now-casts that allow a quick and appropriate response in case of flood risk.

How and when will the installation and implementation of the radars take place?

Interreg NWE IVB fundend the purchase and installation of two dual-polarised X-band radars in Paris and Rotterdam through the RainGain project
The installation of the first radar (owned by École des Ponts ParisTech and co-funded by the Île de France Region through R2DS RadX@IdF and by Veolia through the Chair Hydrology for Resilient Cities) was completed in December 2014. The radar is located in front of École des Ponts, on a tower on the roof of Bienvenüe building. The location was chosen to allow the observation of rainfall upstream of Paris rivers and sewer networks and to facilitate access to students. The installation followed a long period of safety and performance tests as well as consultation meetings with representatives of the users of the building who unanimously supported the project.
The Rotterdam radar is currently under construction on the top of the Nationale Nederlanden office building at the Delftse Poort twin-tower skyscraper complex. Indeed for the possible observations and registration, the rain radar must be placed as high as possible .Other Dutch partners in the Rotterdam-based project besides TU Delft (research) include the Province of Zuid-Holland (co-funding) and Rotterdam City Management Department (co-funding and implementation).