“In our region, the risk of flooding is increasing and the quality of groundwater and watercourses becomes degraded”. It was this twofold assessment that convinced Greater Reims to draw up and then adopt, by its vote on March 30 2023, a sustainable and integrated rain plan, which must be applied to all aspects of regional development (town planning, roads, green spaces, etc.).

Artelia helped it to draw up this plan. Our teams have completely reviewed the traditional and costly way of managing storm water, which consists of discharging it as quickly as possible outside towns, using heavy infrastructure that very often also collects waste water. The thesis work carried out for this project focused on another way of managing storm water, with priority given to its local assimilation by the soil. This limits run-off, which can spread pollution, and massive inputs of water into rivers and water systems, which cause flooding. It also helps to recharge water tables, bring biodiversity back to the city and prevent heat islands.

As part of this project and the associated thesis, Artelia carried out storm water infiltration zoning for the entire inter-municipality territory (almost 1,436 km2, 300,000 inhabitants) and invented a scientific approach to risk planning using statistical mapping. Our teams have also developed a pedagogical method of participatory consultation to help local players and citizens move towards good practice.