This text is part of the special Research section
Rainwater management in our cities mobilizes experts with complementary skills. With her triple training in planning, environmental engineering and agronomy, Danielle Dagenais, full professor at the School of Urban Planning and Landscape Architecture at the University of Montreal and associate researcher at the in Plant Biology (IRBV), contributes to weaving an ecosystem of varied specialists that improves our green and blue infrastructures.
“I do not claim to be a leading researcher in all my areas of intervention, but I am able to play the role of scientific mediator between colleagues from different disciplines”, says Danielle Dagenais on leaving a meeting which allowed her to introduce a researcher in the social sciences to another in engineering. “I am able to understand their language, to translate it and to make connections between them”, explains the one who devotes her career to green infrastructures, spaces which allow in particular to better manage rainwater.
Mimicking the natural environment
Bioretention is a key concept in the work of Danielle Dagenais. “These are stormwater management systems. They make it possible to accumulate runoff water which infiltrates the ground rather than evacuating very quickly into our sewers,” she explains. This approach makes it possible to mimic natural environments. After a rain, there are all kinds of small temporary depressions that fill with water in the fields or forests and, slowly, this water will seep into the ground. “This is what we are trying to reproduce in miniature, in an urban environment”, describes the expert, who aims to reduce waste and sewer overflows and improve water quality through natural purification. by soil and plants.
Danielle Dagenais works mainly on two axes. “At the system level, I am studying, with the team from Jacques Brisson’s laboratory at the IRBV, the effect of soil and plant components and their impact on water. We also determine the criteria for choosing plants to obtain high-performance systems,” she describes.
With Françoise Bichai from Polytechnique Montréal, Martijn Kuller from the Swiss Federal Institute of Aquatic Science and Technology and Laval University and other Quebec and international researchers, she is also interested in planning on a larger scale. “We are working on a multi-criteria tool (technical, environmental, social, etc.) for decision support in order to find the best locations for each type of green infrastructure,” she explains. This tool, developed in Melbourne, must be adapted for use in Quebec and elsewhere. “One of our students is working on criteria related to snow management. This adaptation is carried out in collaboration with multiple partners”, explains Mr.me Dagenais.
Concrete applications
In the field, Danielle Dagenais and her team from the IRBV carry out monitoring work on systems installed in cities. “In Trois-Rivières, we have just completed a hydrological and plant monitoring project, with Sarah Dorner, from Polytechnique Montréal, and Jacques Brisson,” she explains. The research team conducted greenhouse experiments to study the differences in performance between species in order to regulate water volumes and flows, but also to eliminate various pollutants.
“The two components will allow the City to improve the systems that will be implemented later,” predicts the researcher, who also leads projects and monitoring for the Ministry of Transport and the City of Montreal. “We arrived at interesting observations on the choice of species, their location on the site and the maintenance methods. All of this will feed into both the design and maintenance of bioretention systems,” she says.
These researchers therefore work as closely as possible to knowledge users. “You could call this adaptive design: we experiment by implementing a system designed in a certain way and we document its performance, which then allows us to feed back into the design of future systems and improve ourselves”, summarizes M.me Dagenais. She takes as an example the American city of Portland, Oregon. “Very advanced for a long time, it has improved by documenting a lot of the performance of its systems. This is done in parallel with more controlled experiments.
The social acceptability of the solutions, which can promote their success, is also one of the factors that the researcher wishes to understand. Because if, for example, the width of a street is reduced to green the sidewalk, this reduces parking spaces and can raise questions or generate tension. “It’s the positive angle that interests me: what do people like? What do they like less, but why, and how to improve their appreciation? ” she says.
A green and blue laboratory
A few months ago, Danielle Dagenais set up a new laboratory on green and blue infrastructures. This notion covers, for example, waterways (blue) and green areas (green). “You have to think of them as networks, because the spaces, the humans who move about in them and the living organisms in them are linked. And all this has an impact on the management of rainwater and heat, but also on the quality of the living environment of the populations,” she specifies.
With this new laboratory, Mme Dagenais wishes to highlight the interdisciplinary research that it conducts or in which it participates, to create a place of exchange for researchers and to give its students from various backgrounds (in engineering, urban planning, landscape architecture, planning, in sustainable development, etc.) the opportunity to understand the richness of interdisciplinary work by offering them access to dialogue. “Engineering students want to know what their urban planners, landscape architects or social science counterparts are doing and integrate these dimensions into their projects, for example,” she observes.
This unifying project embodies the very essence of Mme Dagenais, which is characterized by the links forged between different disciplines. “I believe that we are moving more and more towards this interdisciplinarity. I’m incredibly lucky to have training that allows me to put it into practice in research work, with very open colleagues,” she says.