Overview ================================== OpenWQ was specifically designed to promote flexible collaboration between modellers, scientists and stakeholders in the design and implementation of biogeochemical reaction networks (easily customizable via `rich JSON-based files `_) in existing hydrological, hydrodynamic and groundwater models (1D to 3D models). The model is written in C++ and benefits from the powerful Armadillo template-based \CC library for linear algebra `(Sanderson and Curtin, 2016) `_ that enables the use of modern, flexible, efficient and compact data structures. The OpenWQ system stems from previous models developed by `Environment and Climate Change Canada `_ and the `University of Saskatchewan `_, particularly `CRHM-WQ `_ (Cold Regions Hydrological Model - Water Quality) that extends the original `CRHM platform `_ (hydrology) model to nitrogen and phosphorus simulations, the `WINTRA `_ framework, the multiphase multilayer `PULSE `_ snow hydrochemistry model, and the `FLUXOS `_ model for watershed hydrodynamic-water quality simulations suitable for Prairie regions. Our vision is to provide a customizable, multi-scale, multi-chemistry modelling framework suitable for flexible model hypothesis testing and uncertainty analysis. This is extremely important in a time of great climate uncertainty. OpenWQ does not run standalone. It runs coupled to existing hydro-models, which makes it ideal for scientists and engineers that want to enable biogeochemical modelling capabilities in their preferred modelling systems. OpenWQ has has been coupled to several models. Explore the `Existing couplings `_ section and learn how OpenWQ can be `coupled to your model `_. .. image:: as_coupler.png `Contact us `_ if you're wondering if OpenWQ could be useful to your research.