A Holistic Study to Conserve Our Great Lakes

Study explores nutrient dynamics to conserve one of Canada’s most threatened water systems.

Twenty per cent of the world’s surface fresh water is found within the Great Lakes Basin, which includes the five Great Lakes and the surrounding lands. This watershed supports an incredible ecosystem but sadly it is one of the most threatened water systems in Canada. A major concern: nutrient export from surrounding agricultural lands into our water sources.

Understanding Watershed Dynamics

Engineering professors, Dr. Jana Levison and Dr. Andrew Binns, along with engineering PhD student Ceilidh Mackie and Dr. Ivan O’Halloran (School of Environmental Sciences), have conducted a field study within the Great Lakes Basin. The researchers seek to understand the nutrient dynamics and the relationship between water quality and land management practices. 

Phosphorus and nitrogen are essential nutrients for plant life and are commonly found in agricultural fertilizers. While these nutrients help plants thrive, they can be detrimental for waters, leading to reduced oxygen, loss of habitats, low species diversity, and impaired drinking water. Levison and the team are one of the first to investigate both surface and subsurface transport pathways of these potentially harmful nutrients in the Great Lakes Basin.

The Full Picture: Water + People

The team monitored six different sites within the Upper Parkhill watershed in southern Ontario, collecting water samples monthly from several sources including groundwater, tile drainage water, and stream water. To get at the full picture and connect experimental research findings with human behaviour, the team also conducted a survey with local landowners to learn about their land management practices with respect to agricultural activity.

The researchers found that there were variations in the nutrient concentrations and in how they were transported from agricultural sites to water source, related to location and time of year. They found minimal concentrations of phosphorus and nitrogen in the groundwater, which was likely related to the geology and land management practices. For example, minimizing soil disturbance helps to reduce erosion and in turn can mitigate the transfer of nutrients from soil to water. However, the predominant form of phosphorus found in the stream water was dissolved, which is more readily used by plants and can therefore promote detrimental algae growth. 

Moving Forward Together

“We suggest that landowners work to incorporate management practices that will mitigate nutrient transport,” says Levison. “Our study has shown initial insights about where and when nutrient-related water quality issues are most likely to occur and is fundamental to developing watershed and land management plans that will help conserve our most precious water resources.”

Jana Levison is an Associate Professor of Engineering at the University of Guelph.

This research project is funded in part by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), through the Ontario Agri-Food Innovation Alliance and conducted in collaboration with the Ausable Bayfield Conservation Authority.

Mackie C, Levison J, Binns A, O'Halloran I. Groundwater-surface water interactions and agricultural nutrient transport in a Great Lakes clay plain system. Journal of Great Lakes Research. 2021 Feb 1;47(1):145-59. doi: 10.1016/j.jglr.2020.11.008