Municipal water management in Canada heavily depends on using Intensity-Duration-Frequency (IDF) curves for 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 web-based tool provides an approach for updating IDF curves under a changing climate and is 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 (Sandink et al., 2016). Thus, one of the primary aims of the tool is to standardize the IDF update process and make the results of current research on climate change impacts on IDF curves accessible to everyone (Simonovic et al., 2016; Sandink et al., 2016 ;Schardong et al., 2020). 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 also directly links Canadian municipalities and the research community, creating opportunities for further research and innovation.

The IDF_CC tool is designed as a simple and generic decision support system to generate local IDF curve information that accounts for the possible impacts of climate change. It applies a user-friendly GIS interface and provides precipitation accumulation depths for a variety of return periods (2, 5, 10, 25, 50 and 100 years) and durations (5, 10, 15 and 30 minutes and 1, 2, 6, 12 and 24 hours), and allows users to generate IDF curve information based on historical data, as well as future climate conditions that can inform infrastructure decisions.

The IDF_CC tool stores data associated with 896 Environment and Climate Change Canada-operated rain stations across Canada (ECCC, 2023). Roughly 700 of these stations have 10 years of data – the minimum time series used by Environment Canada to develop IDF curves for a specific location. Users can also create and share information about their own rain station. Version 8.0 of the tool uses version 3.30 of the Environment Canada IDF dataset, released in October 2023 (Environment and Climate Change Canada, 2022). This dataset is available through the Gauged locations module and is accessible from the main menu of the tool.

The IDF_CC tool also includes the module for Ungauged locations. The ungauged IDF curve estimates, for all durations (5, 10, 15, 30 min, 1, 2, 6, 12 and 24 hrs) and return periods (2, 5, 10, 25, 50 and 100 years), are extracted directly from the gridded dataset produced for the IDF_CC tool and described in detail in Gaur et al., (2020) and in the Technical and User's Manuals (available from the Help menu).

Version 8.0 introduces temperature scaling using the Clausius-Clapeyron relationship as an additional method that is useful for comparing results with the EQM (Equidistant Quantile Matching) algorithm that uses precipitation data. These methods are described in detail in the Technical and User's Manuals (available from the Help menu).

References:

• Government of Canada (2025) CMIP6 statistically downscaled climate datasets, https://climate-scenarios.canada.ca/?page=CMIP6-statistical-downscaling last accessed July 2024.
• Pacific Climate Impacts Consortium (PCIC) (2025) Statistically downscaled climate scenarios, https://pacificclimate.org/data/statistically-downscaled-climate-scenarios last accessed July 2024.
• Environment and Climate Change Canada (2023) Engineering Climate Datasets, available at http://climate.weather.gc.ca/prods_servs/engineering_e.html, last accessed July 2021.
• Department of Energy Lawrence Livermore National Laboratory (2021a) CMIP6 - Coupled Model Intercomparison Project Phase 6, https://pcmdi.llnl.gov/CMIP6/, last accessed July 2021.
• Department of Energy Lawrence Livermore National Laboratory (2021b) Earth System Grid Federation, https://esgf-node.llnl.gov/projects/esgf-llnl/, last accessed July 2021.
• Schardong, A., S. P. Simonovic, A. Gaur, and D. Sandink (2020) Web-based Tool for the Development of Intensity Duration Frequency Curves under Changing Climate at Gauged and Ungauged Locations, Water, Special Issue Extreme Value Analysis of Short-Duration Rainfall and Intensity–Duration–Frequency Models, 12, 1243; doi:10.3390/w12051243, open access, https://www.mdpi.com/2073-4441/12/5/1243/pdf .
• Gaur, A., Schardong, A., Simonovic, S.P. (2020) Gridded extreme precipitation Intensity—Duration-Frequency estimates for the Canadian landmass. J. Hydrol. Eng. 2020, 25.
• Environment Canada (2020): Engineering Climate Datasets, available at http://climate.weather.gc.ca/prods_servs/engineering_e.html, last accessed July 2017.
• Cannon, A. J. (2018). Multivariate quantile mapping bias correction: an N-dimensional probability density function transform for climate model simulations of multiple variables. Climate Dynamics 50(1), 31–49. https://doi.org/10.1007/s00382-017-3580-6
• Sandink, D., S.P. Simonovic, A. Schardong, and R. Srivastav, (2016) “A Decision Support System for Updating and Incorporating Climate Change Impacts into Rainfall Intensity-Duration-Frequency Curves: Review of the Stakeholder Involvement Process”, Environmental Modelling & Software Journal, 84:193-209.
• Simonovic, S.P., A. Schardong, D. Sandink, and R. Srivastav, (2016) “A Web-based Tool for the Development of Intensity Duration Frequency Curves under Changing Climate”, Environmental Modelling & Software Journal, 81:136-153.
• Cannon, A. J., Sobie, S. R., & Murdock, T. Q. (2015). Bias correction of GCM precipitation by quantile mapping: How well do methods preserve changes in quantiles and extremes? Journal of Climate, 28(17), 6938–6959. https://doi.org/10.1175/jcli-d-14-00754.1
• Srivastav, R.K., A. Schardong and S.P. Simonovic, (2014) “Equidistance Quantile Matching Method for Updating IDF Curves Under Climate Change”, Water Resources Management: An International Journal, 28(9): 2539-2562.