Agroecosystems Agricultural intensification is necessary to feed a growing planet, but agriculture puts pressures on downstream ecosystems. My work on agroecosystems is focused on connecting field and watershed scale dynamics to improve our understanding of processes governing nutrient losses to streams. This knowledge is necessary if we are to design effective watershed management and monitoring strategies.
-Cross scale nutrient simulation modelling of Great Lakes watersheds: This work will develop a regional scale mathematical model to evaluate the relationship between nutrient inputs and watershed loading from Southern Ontario watersheds at seasonal timescales. This work is supported by the Ontario Ministry of the Environment and Climate Change.
Agronomic land management survey: Understanding agricultural nutrient cycling is critical to devise strategies to reduce nutrient losses to surface waters. However, nutrient dynamics in agroecosystems are largely driven by the decisions of a multitude of agricultural food producers. This project, called Agri-Model, will seek to understand what decisions agricultural producers are making with respect to land management and why these decisions are being made. This knowledge will be critical when designing policies to reduce nutrient losses from agricultural land and improve water quality in the Great Lakes. It will also be used to inform regional watershed modelling. This work is supported by the Ontario Ministry of the Environment and Climate Change.
Urban Ecosystems Half of all people now live in cities, and this proportion is expected to continue to rise in the coming decades. Urban areas are also expected to grow throughout North America in the coming decades. Understanding how urban watersheds function to transport and transform water, nutrients, and contaminants is necessary to ‘design’ urban areas that keep downstream waters clean.
Fate and Transport of Chloride in Urbanizing Catchments of the Lake Simcoe/South-eastern Georgian Bay Watersheds: In seasonally frozen environments, de-icers (chloride salts) are widely used to maintain safe driving conditions on roads and other impervious surfaces. While the beneficial role of road salts for public safety is unequivocal, the environmental consequences of their use pose risks to stream and lake ecosystems. In the Lake Simcoe watershed (LSW), chloride (Cl) is listed as a pollutant of concern in the 2009 Lake Simcoe Protection Plan, and in-stream Cl concentrations have been increasing in most tributaries since 1993. In urbanized catchments of the LSW, stream Cl concentrations often exceed environmental protection guidelines set out by the Canadian Council of Ministers of the Environment during winter high flows and summer baseflow. The goal of this two year project is to improve our understanding of the dynamics and ecological effects of Cl across a gradient of urbanizing catchments in Lake Simcoe and South-eastern Georgian Bay watersheds. The results of this study will help to inform adaptive winter maintenance management strategies. This project is led by Claire Oswald at Ryerson University, and is supported by Environment Canada’s Lake Simcoe and Georgian Bay Clean Up Fund.
Quantifying Urban and Agricultural Nonpoint Source Total Phosphorus Fluxes Using Distributed Watershed Models and Bayesian Inference: This research examined the functioning of paired urban and agricultural watersheds in Hamilton Harbour’s drainage basin. One of the highlights was that in the Harbour’s urban watersheds, runoff generation continues throughout the growing season, whereas in the Harbour’s agricultural watersheds only baseflow occurs during the growing season. This work helped to select priority watersheds for further monitoring, and helped quantify the nonpoint source total phosphorus flux to the Harbour. This work was undertaken under the supervision of Dr. George Arhonditsis at the University of Toronto, and was supported by the Hamilton Harbour Remedial Action Plan Technical Team.