https://doi.org/10.1080/07011784.2025.2536031

Freshwater quality is a pillar of water security worldwide as countries are becoming
increasingly impacted by contaminants and nutrient loads from human activity, as well
as landscape and climate changes. Reliable water quality predictions play a fundamental
role in tackling this problem. However, water quality predictions are currently unavail-
able for most global rivers and lakes, including those in Canada. Environment and
Climate Change Canada (ECCC) and its partners present here the vision for a physics-
based National Water Quality Model (Nat-WQE; National(e) Water Quality/Qualit#e de
l’Eau) that aims to deliver simulations and predictions of water quality across timescales
from days to decades by building on existing environmental modelling systems and
field data. This commentary also introduces the National Water Quality Modelling
Framework (NWQMF) that has been maturing over the years and provides the basis
and vision for a robust Nat-WQE capable of delivering short- to long-term predictions
of water quality parameters, informing decisions on effluent concentration limits, and
acting as a source-water warning system for Canadians. The NWQMF will produce criti-
cal information that will be available to interested users to inform decisions at various
levels, from local communities to nationwide to international efforts. In this commen-
tary, we summarize (1) the overarching vision and desired outcomes of the NWQMF
and Nat-WQE, (2) a summary of lessons from other large-scale water quality modelling
efforts which informed the modelling philosophy, framework, structure, and associated
data requirements, and (3) the implementation plan, including identifying challenges
and opportunities/synergies for national and international collaborations.

https://doi.org/10.1080/07011784.2025.2536031