When it comes to water, Quebec is fortunate to be well positioned, with hundreds of thousands of lakes, rivers and other watercourses. Given such abundance, it’s easy to think that access to water resources is not an issue for Quebecers and for the many ways they use water.

Climate change, however, contradicts this belief: faced with a future in which episodes of water scarcity will be more significant and potentially more frequent in Quebec, it’s essential to be prepared.

This is the context underlying the Conséquences Attendues Survenant en Contexte d’Aggravation des Déficits d’Eau Sévères au Québec (CASCADES) project, the report on which has just been published. 

Meet Kristelle Audet (Groupe AGÉCO), Laurent Da Silva (NADA Conseils), Daniel Tarte (T2 Environnement) and Jérémie Roques (ROBVQ) for an overview of this initiative. 

What is the CASCADES project?

Kristelle Audet – The aim was to identify the past and future consequences of severe water scarcity episodes in Quebec on ecosystems and also on uses linked to human activities.

Can you give us an example of how the new knowledge generated by the project could be useful to society?

Jérémie Roques – An example that is quite emblematic is the impact of a water deficit episode on the production of and access to drinking water.

Basically, the results of this study, combined with what will emerge from future studies, will be very useful in refining and improving vulnerability analyses of drinking water sources. These analyses are currently rather incomplete in terms of knowledge of the impacts of climate change. The project also enables us to think about emergency planning. What strategies will we use in the event of a severe water scarcity?

The information will be useful to land-use planners: I’m thinking in particular of municipalities and RCMs that have to draw up emergency plans, which could include water deficits. 

The CASCADES project also provides us with useful information for thinking about how to prioritize our actions, and possibly even how to prioritize our uses of water in a context of severe water scarcity. We’re obviously not there yet, but we’ll have to ask ourselves these questions at some point to determine what’s essential for society’s proper functioning.

The ultimate goal remains to ensure that the resource remains available in sufficient quantity for all, always bearing in mind that risks and conflicts over usage must be minimized.

Laurent Da Silva – The issue of prioritizing uses is an important one, and perhaps a bit of an elephant in the room. I have a feeling that this project could perhaps open the door to a conversation on this issue concerning severe water deficit events. Of course, we don’t have all the answers, but the project may enable us to make some headway on this subject.

Why is it important to understand the consequences of water scarcity on populations and ecosystems?

Laurent Da Silva – As far as populations are concerned, we need to understand the impacts in order to be prepared. Let’s just say that when it comes to the hydroclimatic lottery, we’ve been relatively lucky here in Quebec so far in terms of water deficits, but when we look to the future, we can expect water deficits to worsen significantly, particularly in southern Quebec. The idea behind the project is to be prepared; in other words, to be proactive rather than reactive.

The CASCADES project is an opportunity to try to anticipate what the consequences might be in the event of a much more severe water shortage than we’ve experienced to date. 

Daniel Tarte –  I’d say there’s a grey area as far as ecosystems are concerned. We’ve been interested in the impact on people for a long time, because it concerns us directly. But for ecosystems, we don’t know or see what’s going on beneath the water’s surface. We need to know more about the risks we’ll be exposed to when there’s a disruption in the trophic chain—that is, the dynamic interactions between organisms along a food chain—because ultimately, the cascade of consequences also affects humans.

From a strictly ecosystem point of view, I’d also say that it’s very important to understand what’s going on because ecosystems and the species that inhabit them today are the result of thousands of years of evolution. If only to maintain what’s there, we need to know more. 

In closing, how did this project innovate?

Laurent Da Silva – I’ll mention two ways: first, because we wanted to take a holistic view of the subject: to consider the impact on both human uses and ecosystems. We wanted to document the direct and indirect consequences that cascade from an episode of severe water scarcity. 

The second way is that we worked with a narrative framework approach. So, rather than using average temperature and precipitation projections for different climate horizons, we chose to focus on water shortage events found in the climate simulations at our disposal.

In concrete terms, we positioned ourselves in very dry, very hot summer scenarios. These are events that reflect plausible hydroclimatic conditions that could be experienced in the future, to which we add a projection of the socio-economic context: changes in population, water requirements, and so on. 

Working in this way, it was easier to tell the story of this event and to glimpse the consequences for the population, businesses, institutions and ecosystems.