CARACTERISATION QUANTITATIVE ET QUALITATIVE ... - ENGEES

ABSTRACTThe presented study comes within the scope of a will to describe and understand the relationsduring a rainfall between the working of overflow structures, pollution and overflows resultson the natural environment.The « Lille-Marquette » drainage urban area pours out its storm sewage in the “Deûle”through about a hundred of overflow structures. Some of these overflow structures as « TheEsplanade » overflow structure are the subject of a permanent supervision. The first part ofthis study consists in comparing observed overflows and overflows simulated by the MOUSEsoftware in order to improve the overflows prediction. The origin of the difference betweenthe two overflows is detected but must be finalized in the hydraulic model.During the overflows the pollution which is released in the receiver environment depends onthe rainfall. The aim of second part is to find a link between the rain and the pollution flowthrough a measurement survey. The available rainfalls number is restricted. Moreover thereleased pollution depends on a lot of parameters which don’t follow a simple logic. Acategorical conclusion is not possible. Consequently only the thought is presented.Finally a macroscopic analysis by waterway discretization permits to follow the “Deûle”water quality evolution. This part is simplified and limits itself to one overflow structure. Itemphasizes the overflows physical and chemical aspects.Ecole Nationale du Génie de l’Eau et de l’Environnement de StrasbourgLille Métropole Communauté Urbaine5