Research Project Updates

Please check back again soon for research project updates. Examples of recent projects include the following:

1. Changing agricultural landscapes and groundwater quality in sensitive aquifers


Project Summary/Update:

Groundwater is the main source of drinking water for rural communities and many cities in Ontario (~30% of the total population). Nitrogen use on agricultural lands has been increasing over the past decades for higher crop yields. However, over application of fertilizers can result in leaching (transport) of excess nutrients below the root zone to aquifers. Weather patterns can also impact nutrient fate. A comprehensive understanding of cropping systems and their potential impacts on groundwater quality in various geological conditions is necessary to ensure protection of rural water supplies for agriculture and potable water. Field data were collected from 25 groundwater monitoring locations in southern Ontario (Acton, Guelph, and Norfolk County).  Groundwater quality was investigated bimonthly since June 2014 in different groundwater settings (sandy aquifers and fractured bedrock aquifers) under different land uses. The collected samples were analyzed for numerous parameters such as pH, electrical conductivity, dissolved oxygen, redox potential, nitrate, chloride, sulphate, dissolved organic carbon, and isotopes of hydrogen, oxygen and nitrogen. Nitrate concentrations varied with time, depth and location. Each of the three research sites displayed different trends. The Guelph site experienced peaks in nitrate concentrations in spring 2016 after a drought period (summer 2015). The Norfolk site displayed concentrations which align with what is expected from a continuous nitrate source, although certain wells had concentration peaks like the Guelph site. The Acton site experienced consistent nitrate concentrations which did not vary significantly. Evidence from groundwater geochemical analyses suggests that denitrification may be occurring at some of the deeper monitoring wells. A vadose zone model (RZWQM) that simulates both vertical water flow and nitrogen losses in the shallow subsurface was used to quantify the movement of nitrate from different crop types through the unsaturated soil zone to groundwater. Suction-type lysimeters were installed at 40 cm depth in different cropping systems to quantify the nitrate infiltrating from fields into the subsurface (June-September 2015). The RZWQM results produced higher shallow nitrate in Norfolk County compared to the other two sites in similar crop types. The vadose zone concentrations were used as input to the groundwater modelling. HydroGeoSphere software was used for the groundwater modelling to quantify groundwater nitrate, focusing on Norfolk and Guelph. Predictive climate and land use scenarios were evaluated following model calibration. Three climate change scenarios were selected based on their extreme conditions. Three land use scenarios were selected (continuous corn, corn-soybeans rotation, corn-soybeans-winter wheat-red clover). A decreasing groundwater elevation trend yielded from the climate change modelling. Nitrate concentrations are also lower in the future, likely due to changes in groundwater recharge. The continuous corn scenario produced much higher nitrate concentrations compared to the other two land use scenarios. Future extreme climate conditions combined with continuous corn can put an aquifer at risk of nitrate contamination. The BMP scenario performed better regarding future nitrate concentrations; it is recommended that farmers adopt BMPs to avoid the nitrate contamination of groundwater and also increase the farm productivity considering future potential climate conditions. 
 
Monitoring wells in Norfolk County
Monitoring wells in Norfolk County
 

2. Impacts of alkaline stabilized biosolids application on fate and transport of emerging substances of concern in agricultural soils, plant biomass and drainage water


3. Improving crystalline bedrock aquifer conceptual models using novel discrete fracture network methods


4. Source water protection planning for First Nations communities


5. Groundwater use for agricultural production - current water budget and expected trends under climate change


6. Presence and fate of neonicotinoids in groundwater resources in Ontario