As the city expanded around the lake area, the lake went through a period that has been referred to as "rampaging cultural eutrophication," greatly accelerating the natural processes of the lake. Three "cultural" sources of nutrients were added to the inflow of the watershed: fertilizers from the Blenkinsop Valley and Swan Lake farms, effluent from a sewage treatment plant at Quadra and McKenzie (serving almost 500 homes), and two wineries, which between them discharged more than 2,000 kilograms of sludge from the fermentation process into the inflow stream each year.