Achievements, challenges and vision on ensemble forecasting at Quebec’s government
Contributed by Thomas-Charles Fortier Filion
Quebec holds the largest freshwater resource in Canada, with 175,000 km², with more than 500,000 lakes, and 4,500 rivers. It represents 3% of the world renewable water. As in other provinces of Canada, provincial government is the primary manager of water, responsible for most of the environmental regulation, and policy making that affects water issues.
Hydrological forecasting is ongoing in Quebec since the 70s. The main organisations developing forecasting tools are Hydro-Quebec, and Rio Tinto Alcan, mainly for the optimisation of hydroelectricity production, and the CEHQ (Centre d’expertise hydrique du Québec) for conciliation of multiple uses for public dams, and public safety.
CEHQ is an agency of the Quebec’s Ministry of the Sustainable Development, the Environment and the Fight Against Climate Change (in French, Ministère du Développement durable, de l’
The Governmental Quebec’s flood forecasting service was set up after the major 1996 Saguenay’s flood. Since the late 90s, CEHQ has been forecasting for public dam management.
There are 700 public dams (44 managed in real time), which have multiple objectives and usages (water supply, flood control, leisure, energy production, etc.).
In 2011, a major flood occurred in the Richelieu River Basin and authorities have decided that flood forecasting for public security purposes would also be developed.
CEHQ flood forecasting team has 2 coordinators, 7 operational forecasters, 2 computer scientists and 1 science advisor. To become a ‘supervisor forecaster’, a forecaster has to go through several levels of training as shown below:
- improve flood forecasting tools, focusing on the post-processing of uncertainties including calibration, and application of error models. Two models have been tested: one depending on forecast horizon and season, the second model depending also on the mean flow over the past 6 hours;
- improve the dissemination of the forecasts on internet (historical and real time data, as well as forecasts). See here for an example of dissemination.
Main operational issues for the implementation of ensemble streamflow forecasts are:
- Public Security:
- Quantification of the uncertainty on the timing of the peak flow is crucial.
- Dam management:
- Tools to assist in decision-making are both complex and rare.
- There is no absolute criterion helping decision-making for multi-purpose dams available.
- Decisions based on the deterministic forecasts are easier to explain.
- Uncertainty evolves quickly in short terms.
- Rapid availability:
- Decision support needs to be developed.
- Acquisition time and running time need to be improved (currently, forecasts are available around 10 am).
Finally, at CEHQ, operational developments go hand in hand with collaboration with research institutes. Our main collaboration today is with Université Laval, Chaire de recherche EDS en prévisions et actions hydrologiques (CRPAH).