Large-scale water quality modeling to screen for risks in Canadian and global freshwater bodies using a high-resolution river routing approach

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Protecting the quality of our surface water resources is of paramount importance to preserve the health and safety of humans and aquatic ecosystems that depend on them. To successfully maintain the ecosystem services of rivers and lakes, including the supply of drinking water, we need to be able to monitor and predict critical water quality characteristics that sustain aquatic habitats and biodiversity, such as water temperature and sediment concentrations; and we need to understand the sources, fate and distribution of potentially harmful substances affecting them. This importance has been internationally recognized by nominating the provision of clean water as a central Sustainable Development Goal. Since water quality in the river system is sensitive to both climate change and anthropogenic activities, and effects can accumulate or propagate over long distances along the river network, there is an urgent need to better understand relationships between surface water and human perturbations at large scales, i.e. for entire basins, countries, and the world. My proposed research program over the next 5 years aims to enhance global hydrological modeling schemes in order to analyze current and future water quality trends that put Canadian and global freshwater resources at risk. I will focus on three specific research frontiers: (a) I will create a modeling approach to estimate water temperature regimes for all rivers and lakes globally at high spatial resolution, based on combining global air temperature with a flow routing scheme, taking glaciers, snow, and groundwater into account. (b) I will develop a global modeling framework to estimate sediment transport and its possible changes at high spatial resolution. And (c) I will complete the development of a chemical fate model that is capable of estimating concentrations of emerging contaminants in our waterways, such as down-the-drain household chemicals, pharmaceuticals, industrial pollutants, microplastics, or nanoparticals, covering all of Canada and ultimately the world. For the proposed research program, my students will blend state-of-the-art methodologies from Geographic Information Science (GIS) and Remote Sensing. The seamless global data that I have produced over the last decade in my research lab, including high-resolution maps of 8.5 million river reaches and 1.4 million lakes, combined with new modeling techniques will allow for first-time studies at pan-Canadian and global scales that have previously been unachievable. The main goal is to develop a model and scenario framework capable of screening for regions at risk, in particular at critical locations such as drinking water intakes. I anticipate broad applicability of my results for strategic freshwater planning and integrated river basin management, including assessments of the effects of domestic or industrial water use, agricultural land use practices, reservoir operation, and climate change on downstream water quality.