Mechanics and Modelling of Agricultural Nonpoint Source Pollution

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The long-term research goals have been to develop practical approaches for environmentally sustainable nonpoint source pollution control, including watershed based source water protection and nutrient management. Development of such approach; needed for food security, environmental sustainability, soil resilience for sustainable food production and for future capacity building; will provide means to assess the effect of structural and non-structural best management and water management practises on the health of the water bodies in a watershed. Development of such approaches also require better understanding and description of hydrologic variable and processes affecting seasonal hydrology, their impact of stream flow pattern and adopted best management practices on nutrient loads. This research focuses on the quantification of the changes in the stream flow regimes due to climate change, development of an easily use-able screening approach for the application of non-point source pollution best management practises, and the development of an innovative approach to evaluate the performance of structural and non-structural best management practises adopted to control and improve stream water quality in Ontario's unique seasonal climatic conditions. This approach will lead to the development of tools for effective management of sediment and nutrient non-point source pollution due to agricultural land use activities. The proposed goal will be achieved by (i) quantification of the effect of climate change on hydrologic variables such as seasonal stream flow pattern, temperature and precipitation regimes, (ii) by development of an easily usable screening approach to identify the location of sediment and phosphorus sources for application of best management practises in a watershed, and (iii) by development of an event based watershed model having the capability to explicitly evaluate the impact of seasonal rainfall events and structural best management practices such as pipe inlets and blind inlets, and non-structural best management practices such as within watershed and along the stream vegetative filter strips adopted for non-point source pollution control. This research will provide a tool to evaluate the impact of road side ditches and variable field boundaries on sediment and nutrients delivered to the stream. This research will also provide a simple screening tool to identify the location for the application of best management practises in an agricultural watershed. Though the focus of this research has been the Ontario conditions, the results will be applicable to other regions of the country. The ultimate beneficiary will be society and humanity, who will be benefited from potential source water protection and water quality improvements.