Indice de qualité de l'eau pour détecter l'impact de la pollution diffuse urbaine
This study fits into the scheme of research work being carried out to control stormwater rejects. Its main objective is to represent, with the help of a water quality index, the deterioration of the quality of the Saint-Charles River, caused by the combined sewer overflows of Quebec City, Canada, during a rainstorm. The proposed quality index has been applied to evaluate the recreational use of the river.The overall results obtained in the case of a 20 mm rain show index values that characterize a water of poor quality. Moreover, within the region of the combined sewer overflow, a minimum delay of 24 h is necessary to allow the water quality of the Saint-Charles River to return to the level where it was at the dry period, which generally has a value less than the critical value for recreative use. Key words: water quality index, urban runoff, water pollution, nonpoint source of pollution, water quality, water use, environmental impact, pollution control.