Impacts of climate change on spring runoff
In the coming years, Québec’s water regimes will be affected by climate change, with the changes varying according to the regions and seasons.
The data on climate change shows that the volume of spring runoff will increase north of the St. Lawrence Valley but decrease in the far south of the province. Yet, the trend is uncertain for most of the southern area, as illustrated in the figure below. Province-wide, the day when the spring runoff’s peak water level occurs is expected to be progressively earlier, advancing by 15 to 24 days by 2080.
Direction of change in average maximum flow over 14 days in winter and spring for a 20‑year flood (Q14MAX2HP) – 2080, RCP 4.5 scenario, compared to the period 1981‑2010.
Blue: increase
Red and orange: decrease
White: no change
The magnitude of summer and fall flooding will increase throughout Québec, with certain areas facing increases of more than 25% due to extreme precipitation events of increased scale and frequency.
Magnitude of relative change (%) in the maximum daily flow in summer and fall for a 20‑year flood (Q1MAX20EA) – 2080, RCP 8.5 scenario.
Managing climate change: what we are doing to adapt
After the Saguenay flood in 1996 and the ice storm of 1998, our company became keenly aware of the challenges posed by climate change. In the aftermath of such extreme climate events as these, Hydro‑Québec became one of the founding partners of Ouranos, a globally recognized consortium on regional climatology and adaptation to climate change. Through this partnership, Hydro‑Québec is at the forefront of knowledge concerning the impact of climate change on hydropower facilities and related assets, particularly in terms of hydrology.
In 2022, Hydro-Québec released its first Climate Change Adaptation Plan, which laid out the measures it has targeted to address challenges related to grid design and operation, the effects of extreme weather events, and worker health and safety.
A number of adaptation measures are related to increasing the resilience of our control structures. For example, Hydro‑Québec is developing climate and hydrological data portals based on the future climate for internal use. The company is also preparing guides and training courses to help staff incorporate climate change considerations in their activities.
While the planning and design of structures should reflect climate forecasts, dam management requires the ability to adjust to the major flow variations that already occur in Québec’s rivers. This is a skill that we have been developing and cultivating for decades.