GWFO event recap
Why Groundwater Data Matters to Cities
October 26, 2026
1PM CST
Webinar
Zoom Recording Available
GWFO Webinar Series Travels to Southern Canada
University of Waterloo’s Professor David Rudolph from the Department of Earth and Environmental Sciences and the Water Institute, shares experiences from instrumented sites in rapidly urbanizing regions of southern Canada.
Professor Rudolph was introduced by GWFO User Advisory Panel member, Sameer Dhalla with the Toronto and Region Conservation Authority.
Why Groundwater Data Matters for Cities
GWFO User Advisory Panel member, Sameer Dhalla, Director of Development and Engineering Services at Toronto and Region Conservation Authority, introduced David Rudolph, University of Waterloo’s Water Institute Professor in Earth and Environmental Sciences, who opened by providing a bigger picture of groundwater resources globally and how they are used in Canada.
95% of liquid freshwater on planet earth is groundwater. In Canada, groundwater is one of the most important freshwater resource, supplying drinking water for many communities and supporting streams, wetlands, and urban water systems. Urbanization can alter natural groundwater recharge through paved surfaces and land-use changes, making it increasingly important to understand how much water is available and how it moves through the landscape. Effective groundwater management depends on long-term monitoring and high-quality data to ensure that growing cities can maintain sustainable water supplies while protecting connected ecosystems. .
Managing Groundwater in Growing Urban Centres
A key focus of the presentation was the challenge of balancing urban growth with groundwater sustainability. Using the Municipality of Waterloo as an example, Professor Rudolph demonstrated how communities that rely heavily on groundwater face risks related to over-extraction, contamination from sources such as road salt and nitrates, and impacts to streams and wetlands. As populations grow and demand increases, comprehensive groundwater data becomes essential for understanding water capacity, protecting water quality, and guiding long-term planning decisions. The webinar emphasized that data-driven management is critical for ensuring reliable water resources in rapidly developing regions.
The Importance of GWFO Data and the Alder Creek Observatory
The Global Water Futures Observatories (GWFO) network plays an important role in collecting, managing, and sharing the data needed to address these challenges. The Alder Creek watershed, which supplies approximately 25% of groundwater capacity for the surrounding cities, demonstrates how coordinated monitoring can support research and decision-making. Through weather stations, monitoring wells, stream gauges, and water quality measurements, the observatory generates valuable datasets used to identify groundwater discharge hotspots, track contaminant movement, and improve hydrological models. By making data openly available and connecting researchers, water managers, and partners across Canada, GWFO helps transform such local observations into knowledge that can support sustainable groundwater management nationwide.
Q&A
Q: What is the depth to water table - are new monitoring sites easy to install? Have you thought about continuous surface water quality monitoring?
Professor Rudolph's Response:
Across the Alder Creek watershed, the topography is gently rolling and often referred to as hummocky. The depth to the water table is quite variable depending on both the position on the landscape and the nature of the overburden material, which varies between permeable sand and gravel and low permeability silts and clays. Near wetlands and streams the water table is at or very near ground surface and in these regions, it is very easy to install monitoring wells manually. Along the topographic highs, the water table depth can be greater than 10 m and a small drill rig is normally used. However, even these deeper installations are not difficult. Gaining permission and access to a site of interest is usually the most challenging step. At three separate locations along the main channel of Alder Creek, we have instruments that collect continuous depth, temperature, electrical conductivity and nitrate concentrations. I had forgotten to mention this during the webinar. We are hoping to increase the coverage of continuous surface water quality monitoring as you suggest, and we are in full agreement with your recommendation.
Q: Is my understanding correct that this is an actively recharged system? Do the datasets include environmental isotope data?
Professor Rudolph's Response
The Region of Waterloo currently employs a Managed Aquifer Recharge (MAR) process, consisting of an Aquifer Storage and Recovery (ASR) system where treated surface water from the Grand River is injected into the production aquifer units at a point of high elevation within the Waterloo Moraine. Currently, there are discussions and considerations focused on expanding and diversifying the MAR systems to enhance the overall capacity for the long-term supply of the Region. The Alder Creek Observatory is being considered as a location for evaluation of new MAR options.
Currently, water environmental isotopes (2H, 18O and Tritium) are routinely collected within the watershed both from the surface water and the groundwater.
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