Grant: Strategic Projects - Group

Population growth in Canada is increasing the pressure on freshwater systems for two essential but diametrically opposed services: the provision of drinking water and the assimilation of wastes. In many cities, wastewater treatment plants (WWTPs) discharge effluent directly into rivers. WWTP effluent is the largest human impact by volume on freshwaters in Canada. We will focus on the largest Canadian watershed feeding Lake Erie, the Grand River, where several agencies and regulators require information for science-based management. The Grand River watershed is home to 950,000 people. Projected population increase is over 40% within 20 years. Currently, more than 500,000 people rely on the Grand River for drinking water while there are 26 WWTPs along the river. Non point source nutrient loads are also extremely high, as agriculture (including large livestock operations) is the dominant land use. To accommodate this new growth, billion dollar decisions for wastewater and drinking water treatment and agricultural land management have been taken. Two major wastewater treatment plants will be modified to change the form of nitrogen (N) released to the river. Further investment may be needed in the future to control phosphorous (P) load. This research project capitalizes on a unique opportunity to study the river before and after this major alteration. A comprehensive approach to understanding and modelling the P, N and oxygen (O2) cycles is planned. We will use year round field sampling, laboratory experiments and new natural isotopic techniques developed by our research group to understand the important processes of nutrient cycling and to separate agricultural from WWTP contributions to low O¬2 at night and high levels of N2O, nitrate, P and ammonia in rivers.