Computerized Tool for the Development of Intensity-Duration-Frequency Curves under Climate Change

NEW PUBLICATION: "A decision support system for updating and incorporating climate change impacts into rainfall intensity-duration-frequency curves: Review of the stakeholder involvement process": A new paper has been published in the Journal of Environmental Modelling & Software. ( (Jully 18, 2016)

CLIMATE MODELS DATABASE EXPANDED: The current version of the tool includes two additional global climate models. They are EC-EARTH from from ICHEC, EU and GFDL-ESM2M from NOAA GFDL, USA. Now, 24 climate models are available within the tool for your analyses. (April 21, 2016)

NEW PUBLICATION: "A web-based tool for the development of Intensity Duration Frequency curves under changing climate": A new paper has been published in the Journal of Environmental Modelling & Software. ( (April 13, 2016)

NEW FEATURE – Viewing Uncertainty: A new feature has been added to the tool to allow users to quickly assess uncertainty associated with generation of future IDF curves using different GCMs. Users can now quickly view the distribution of outputs generated by each of the 22 GCMs available in the tool in the form of box plots. Users must select the “All Models” GCM option when generating future IDF curves and then the “Box Plot – Uncertainty” tab when viewing future IDF curves to view this feature. (April 04, 2016)

Municipal water management in Canada is heavily dependent on the use of Intensity-Duration-Frequency (IDF) curves in planning, design, and operation of municipal water infrastructure. Many watershed management activities also rely on the use of IDF curves, including those related to water supply, water quality management and flood control. This project focused on updating IDF curves under a changing climate and developing an accessible, web-based tool available to anyone interested in developing IDF curves that incorporate projected climate change impacts.

While there is a need in almost every Canadian municipality to adapt to changing climatic conditions, there is a lack of necessary expertise within municipalities for implementing current research related to the impact of climatic change on IDF curves. Thus, one of the primary aims of this project was to standardize the IDF update process and make the results of current research on climate change impacts on IDF curves accessible to everyone. The developers and supporting agencies believe that a freely available, computerized IDF update tool will aid in the selection of effective climate change adaptation options at the local level, advancing the decision making capabilities of municipalities, watershed management authorities and other key stakeholders. The tool will also provide a direct link between Canadian municipalities and the research community, creating opportunities for further research and innovation.

This computerized web-based IDF tool integrates a user interface with a Geographic Information System (GIS). By creating or selecting a station the user will be able to carry out statistical analysis on historical data, as well as generate and verify possible future change based on a methodology using a combination of global climate modeling outputs and locally observed weather data.

To access functionalities and explore advanced options (for example, provide your own data/stations and carry out analysis for future scenarios using Global Circulations Models), please create your account or login if you have an account already.

By accessing any of the above options you agree with the Terms of Use

We also encourage you to check out the user manual and technical documentation available in the Help section.

For more information on IDF curves, climate change, please see:
CSA document on IDF curves:

The current version of the Tool includes version 2.30 of Enviroment Canada IDF dataset from 21/Dec/2014 available at:

Please contact us using this form to send comments, report suspected bugs or suggest modifications to existing features.

Dear IDF_CC users,

The development team is very excited to inform you that Version 2 of the tool is now available for beta testing. With the Version 2 we are (i) improving communication with the tool through a new user interface; (ii) using the “state of the art” in climate modeling by providing a new set of climate data; and (iii) significantly improving statistical analysis of IDF relationships.

Main features of the updated version include:
  • A new user interface: A friendly and efficient user interface provides for easy communication with tool database and modelbase.
  • Bias corrected climate models: The Global Circulation Models (GCMs) used with Version 1 have been replaced with bias corrected models developed by the Pacific Climate Impacts Consortium (PCIC) for Environment Canada. Statistically downscaled daily Canada-wide climate scenarios, at a gridded resolution of roughly 10 km for the simulated period of 1950-2100 are used in the Version 2 of the tool. Daily precipitation from nine climate models bias corrected with two methods are used, resulting in 18 climate model datasets. The data is available for three Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5).
  • Generalized Extreme Value (GEV) distribution: Version 2 of the tool uses GEV as the primary distribution to fit and update IDF data. The Gumbel distribution used by Environment Canada for fitting the IDF data is outdated and is only kept within this version to provide users with the opportunity to compare official IDF curves obtained using historical data with those obtained by the IDF_CC tool. Many recent studies have shown that GEV distribution provides better fit to annual maximum precipitation (AMP) series.  The IDF updating procedure has also been modified to reflect the use of the GEV distribution.
Version 2 Technical Manual and User’s Manual provide the details of all the changes implemented with the Version 2 of the tool.

Users are strongly encouraged to share their comments and questions with the development team and directly contribute to the beta testing of the Version 2 of the tool.