Management Strategies for Eutrophication and Macrophyte Growth in Two Urban Lakes in Saint-Bruno, Quebec

Abstract Two small, shallow lakes (Ruisseau and Village lakes), located in Saint-Bruno near Montreal (Québec), were studied in 1987 to determine the extent of, and to propose alleviation solutions to eutrophication and to macrophyte growth. Flows and various water quality parameters were monitored in the influents and in the lakes, and macrophytes were harvested at four different locations in Village Lake. Both lakes were found to be highly eutrophic. The dominant plant specie was found to be Myriophyllum spicatum. Biomass densities were high with values of 206, 212 and 395 g/m2 at three of these sampling locations. A number of alternatives which could mitigate eutrophication and the presence of macrophytes are discussed in terms of technical feasibility and cost. Source control of nutrients, along with citizens involvement, and partial control of macrophytes were recommended management strategies.