The Tobacco Creek Model Watershed is located in south-central Manitoba and is an important site for Global Institute for Water Security researchers studying the effects of agricultural Beneficial Management Practices (BMPs) on hydrology and biogeochemical cycles. BMPs are used to reduce nutrient loads to sensitive aquatic ecosystems and mitigate the effects of flood and drought. But, despite widespread application, there remains little information on their effectiveness.
“Tobacco Creek is one of the most data-rich watersheds in Canada, where more than 20 years of research has been targeted to understanding the effectiveness of several BMPs,” explains Helen Baulch, research lead. “This long history has been incredibly valuable for our research into understanding the nutrients and hydrology of the watershed and is helping us develop potential solutions to eutrophication problems in Lake Winnipeg and beyond.”
Postdoctoral fellow Taufique Mahmood and masters student Jennifer Roste are modelling the hydrology of the creek and developing new tools to understand nutrient export and its controls. So far, Mahmood’s work suggests that field stubble height is an important determinant of snowpack and spring streamflow. He’s also shown that although the small dams that farmers construct throughout the watershed do reduce peak flows, the impact is fairly small in flood years.
Also part of the research team are masters students Raea Gooding and Noel Galuschik. They completed an extensive field program to understand nutrient dynamics within Tobacco Creek’s tributaries and ask the question: ‘Do sediments alter stream nutrient concentrations and will this interaction yield a net benefit to water quality?’.
Final results aren’t expected until later this year, but Gooding’s work suggests that streams and dams are important sites of permanent nitrogen removal, with dams in particular having a high capacity to retain nitrogen, which will help improve water quality. Unfortunately, both dams and streams are susceptible to nitrogen saturation. Galuschik’s work shows that stream and dam sediments often have the capacity to absorb phosphorus from the water column. She is looking into identifying important sites for phosphorus retention and why these may change over a season.
This research is funded by the Canadian Water Network with GIWS members and students working in collaboration with Tobacco Creek Model Watershed and Environment Canada researchers. Local community members, farmers, government officials and other stakeholders are kept informed of research findings and offered the opportunity to voice their opinions, suggestions or concerns.
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