The firm intention to make the Rivers Seine and Marne clean enough to swim in by 2024 has imposed a need to act to improve their water quality. One initiative would be to increase by 5% the area of the territory to be disconnected from the main water network. An ambitious aim in a context where the tendency is to seal the ground. In order to give practical support to the major changes in rainwater management, Apur has published a study in the form of a toolbox and a cartographic methodology for use by all urban key players.
Rainwater management upstream of the network is crucial to improving the quality of water discharged into the natural environment: every drop of rain that does not end up in the sewers makes sewage treatment easier and reduces the risk of the network overflowing and being discharged into the rivers. Local rainwater management can reduce the volume of water in the network, the volume to be treated and last but not least, the water bill.
In response to this aim of increasing local management, Apur has drawn up a method of cartographic analysis of watersheds and created an initial toolbox to identify the possibilities of disconnecting impermeable surfaces in Paris and the metropolis. The various levers to be used to set up local management are enumerated there as well as the main possibilities in each type of location. In this way, for example, it can be seen that in Paris the greatest potential for disconnection is to be found mainly in public and private land plots rather than on the streets.
NB: this study and the two cartographic collections which accompany it were drawn up by Apur within the framework of reflection and discussion of the work group “Water quality and swimming” set up by the Mayor of Paris and the Regional Prefect with the 2024 Olympic and Paralympic Games in mind. They were held in conjunction with the City of Paris Department of Sanitation and Water and the working sub-group “Prioritising water discharge into the Rivers Seine and Marne”, piloted by the Paris Conglomeration Interdepartmental Sanitation Syndicate (SIAAP). They will be developed to be more useful practically with the sub-group “Rainwater management”, coordinated by the Seine-Saint-Denis Departmental Swimming Committee (CD 93).
