Nutrient balances (phosphorus and nitrogen) in Lake St. Charles, Quebec, and the evaluation of effectiveness of remediation scenarios for nutrient reductions on the lake's water quality
Lake St. Charles is the primary drinking water reservoir of Quebec City, Canada, providing water to about 300,000 people. Over the past decade, several occurrences of blue-green algae (cyanobacteria) bloom have been recorded, affecting the quality of water in this strategic reservoir. Evaluation of observed data collected over the past decade indicates that the water quality of the lake is undergoing fast degradation due to anthropogenic activities around the lake and in the watershed. Further evaluation of field observations and their interpretation showed that the biweekly gaps between measurements, especially at high flow events, and lack of inclusion of all tributaries in previous studies produce uncertainties that decrease their suitability for making sound management decisions. Hence, to make better use of available data and to support decision making, this project aims to link water quality data from different sources with geomorphic, hydrometric and meteorological data through a comprehensive water quality model; providing a framework to assess the effect of various sources of nutrients on the water quality of Lake St. Charles. Model outcomes would help quantifying the relative amount of nutrients from each source to the lake.