CSHS Resources


GreyJay is a hub created to promote, preserve and advance hydrological modelling capability in Canada. Hydrological processes in Canada are as varied as the landscapes they occur in and there is no one-size-fits-all model. Many good models have been developed by practitioners and academics and are being used in a wide variety of applications. GreyJay offers a place for these models to reside, develop and be shared – all at no charge to developers and users.

Users can find downloads and links to all the known hydrological models and software in Canada. If the project is on GreyJay, the executable and supporting documentation can be downloaded right from the GreyJay server. There is also a forum for each project where users and developers can connect to ask and answer questions. If the developer has designated the project as open source, users can also access the source code.
Developers have access to a wide range of development and backup tools that are customized to your needs. GreyJay offers versioning systems via Git and SVN protocol, automated backups of source and compiled code, issue tracking, secure user logins and user permission settings, and the ability to designate your code as open or closed source.

Some of the projects already on GreyJay are: Raven, hydRology, MESH, WATFLOOD, HBV-EC (coming soon), and WDPM (coming soon). Please visit the Projects tab for a complete list.

GreyJay is operated by the CSHS, which is a non-profit that promotes hydrological sciences in Canada. GreyJay receives support from organizations like National Research Council, Github, and Manitoba Hydro. If you like what CSHS and GreyJay does, please consider contributing your time or resources to the project.


Raven is a robust and flexible hydrological modelling framework, designed for application to challenging hydrological problems in academia and practice. This fully object-oriented code provides complete flexibility in spatial discretization, interpolation, process representation, and forcing function generation. Models built with Raven can be as simple as a single watershed lumped model with only a handful of state variables to a full semi-distributed system model with physically-based infiltration, snowmelt, and routing.


hydRology is an R package of functions used by Canadian hydrologists. It contains functions for statistical hydrology, basic data manipulation, visualization, spatial hydrology, and streamflow measurement analysis.

Source code can be accessed on Github


MESH (Modélisation Environnementale communautaire – Surface Hydrology) is the hydrology land-surface scheme (HLSS) of Environment and Climate Change Canada’s (ECCC’s) community environmental modelling system. MESH allows different surface component models to coexist within the same modelling framework so that they can easily be compared for the same experiment using exactly the same forcings, interpolation procedures, grid, time period, time step and output specifications.


WATFLOOD is an integrated set of computer programs to forecast flood flows or do simulations for watersheds having response times ranging from one hour to several weeks. The emphasis of the WATFLOOD system is on making optimal use of remotely sensed land cover data, digital elevation models and numerical weather data.

Frequently Asked Questions

What is the bus test?

While a little gruesome, the bus test is an easy way to find out how sustainable a project is. If the lead developer of a project was hit by a bus today, would the project continue? Or would it be shelved?
There are many good hydrological models that have been built across Canada, but many of them don’t pass the bus test. CHyMS was created to address this problem by creating a central repository where developers can safely store, access, develop and publish their models. Developers can choose what protocol to use (Git or SVN) and who they want to participate in development. The goal for CHyMS is to bring developers and users together so that good projects can pass the bus test.

What is the difference between NRC and Github?

CSHS offers two different methods of source code control to provide maximum flexibility to developers. NRC’s CHyMS uses SVN protocol and its server and services are located that the National Research Council. Github uses the Git protocol and Github for server and hosting services. There are advantages and disadvantages to using either method and the model developer must decide what suits them best.

What is the login information for NRC?


and log on:

What is the login information for Github?

Users can create their own account through Github. For access to the source code of private repositories, they can request access from the owner of that repository.

Why can’t I access the source code to some of the projects?

Not all of the projects on CHyMS are open source. Project creators can decide if they want their code to be open to the public or a team of developers.

Does CSHS charge fees?

No, CSHS does not charge fees for users or developers. CSHS is a non-profit initiative and relies on donations. The National Research Council is happy to provide development support for projects wishing to have an extra level of service (for a fee). Github is free and always will be.

How can I get my project on GreyJay?

Please contact cshs@cwra.org.

Why shouldn’t I just use my personal Github account to store my project?

Often it makes sense to go this route. Github offers a few advantages over a personal Github project. Most importantly, the project will be plugged into a whole Canadian hydrology community by having it on chyms.ca. Secondly, Github offers private repositories and user permissions, should a developer wish to have more control over their project. Lastly, by giving the CSHS committee access to your project, you making great progress towards passing the bus test.

Who actually uses these projects?

Some of the end users of hydrological models on GreyJay are:

  • BC Hydro
  • Environment and Climate Change Canada
  • International Joint Commission
  • Lake of the Woods Control Board
  • Manitoba Hydro
  • New Brunswick
  • Ontario Power Generation
  • University of Waterloo