Can Groundwater Protection and Agricultural Production Co-exist over Vulnerable Aquifers?
University of Calgary
The Abbotsford Aquifer is a vulnerable water supply aquifer whose average nitrate concentrations have exceeded drinking water standards for more than 15 years. The long-term groundwater nitrate monitoring shows little overall trend with time, although shorter-term fluctuations in the shallowest monitoring points suggest management can affect groundwater nitrate concentrations locally. Soil nitrogen budgets show excess nitrogen is available for leaching. Although there is consensus that agricultural management practices have changed in the past few decades, there is no objective assessment of their extent or whether they are affecting change in the aquifer. It is unclear if adoption of best agricultural management practices alone will be sufficient to protect water supplies in this vulnerable aquifer. Contaminated groundwater flows south across the international border, making it a long-term transboundary issue. We have been working towards delineating and monitoring groundwater nitrate leached from a particular field in order to directly link soil management with groundwater impacts. This work, and complementary numerical modeling efforts, will provide insights into the agricultural management and climatic controls on nitrate leaching. However, there is currently little effective policy or legislation to deal with the ongoing situation. If groundwater protection requires changes to management practices that put growers at an economic disadvantage in global markets, how then do we move forward?