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Canada1Water: Application of Climate Models to Forecast Changes in Freshwater Quantity

Freshwater is a vital resource for the health, security, and economic stability of Canadians, supporting domestic use, agriculture, fish habitats, industry, and natural resource development. Approximately 75% of Canada’s freshwater is found in shallow groundwater—three times the volume of surface water—yet Canada currently lacks a national system to quantify groundwater resources and forecast future availability.

The Canada1Water project aims to address this critical gap by leveraging cutting-edge freshwater modeling, informed by dynamically downscaled regional climate models, to develop a comprehensive framework for assessing and forecasting Canada's freshwater resources. This framework integrates the latest data and models to provide robust projections under changing climate conditions.

Phase I of the project focused on research and development, assembling harmonized, national-scale datasets representing groundwater flow (geology, permafrost), surface water dynamics (channel networks, topography), and climate drivers (precipitation, temperature). These datasets were applied using the Weather Research and Forecasting Model (WRF) to dynamically downscale climate models, and a fully integrated groundwater-surface water model (Hydrogeosphere, HGS).  The WRF model has a spatial resolution of 12 km to 24 km, and daily timesteps are integrated to monthly means to drive the HGS model. The HGS model uses a finite element model mesh with a spatial resolution ranging from 1 km near the stream network to 5 km distally. Model calibration was based on a 30-year historical period (1981 to 2010), and mean annual projections were generated for the middle 20 years, and final 20 years of the 21st century.

Phase II, launched in April 2024, is dedicated to analyzing and assessing the model outputs. A key component of this phase is the comparison of simulation results with total water storage data from the Gravity Recovery and Climate Experiment (GRACE), allowing for comprehensive model validation. Additionally, nested models offer high-resolution insights to support climate adaptation planning. Due to the effects of evapotranspiration, permafrost, and groundwater storage, the relationship between precipitation changes and water storage or surface water flow is non-linear, and heterogenous across Canada. Understanding these non-linear interactions is key to future land and water management within Canada. Key metrics of freshwater availability and trends, from historical baselines to future scenarios, are being made publicly accessible, offering actionable insights for land and water management in Canada and drawing international interest from countries facing similar challenges.

Host: Mani Mahdinia
Event series  Atmospheric Physics SeminarsNoble Seminar Series