Efficacité de la récupération des eaux de pluie dans la réduction des débordements de réseaux. Le cas du « Village Parisien » à Champigny sur Marne (Ile de France) Efficiency of distributed water harvesting on runoff reduction. Case-study of "Village Parisien" district, Champigny-sur-Marne, Ile de France

In the « Village Parisien » district, in Champigny-sur-Marne, several sewer overflows have been observed. The district (23 ha) is mainly occupied by detached private housing. On 30% of the houses, the county administration installed cisterns for roofs rainwater harvesting. This paper describes a hydrological analysis of the district before and after cisterns installation. We calibrated the SWMM 5 hydrological model using a genetic algorithm, on the basis of sewer flow measures before and after the installation. Simulations show that, although cisterns affect the district hydrology, they can not prevent sewer overflows in case of heavy rain events.