Session C4 - Multi-criteria decision-support for managing SCMs

The implementation of green infrastructure (GI) requires a planning approach that takes into account the complexity and interdependence of urban issues. To facilitate this planning process and support decision-making regarding the location of GI, numerous digital mutricriteria planning support tools (PSS) have been developed. The SSANTO (Spatial Suitability Analysis TOol) tool, adapted from the Australian context to Quebec with two large cities of over 100,000 inhabitants, is a such a tool. However, the transferability of this tool to small and medium-sized municipalities remains uncertain due to significant differences in planning objectives in particular related to GIs. In order to determine the issues and development objectives for priority GIs in their urban context, two online workshops were held with municipal professionals from two small towns in Quebec. Participants completed two online questionnaires to determine local preferences and prioritize planning objectives specific to their communities. Preliminary results show that the hydrological performance of green infrastructure is the top concern for both municipalities, followed by costs and climate change adaptation.

Urban expansion has intensified drainage problems such as flooding and overload of conventional systems due to soil sealing and increased surface runoff. This study presents the development and application of an automated spreadsheet designed for hydrological and economic analysis of Compensatory Techniques (CT) in urban drainage projects. The tool, structured into eight thematic tabs, enables precise simulations and comparisons among different scenarios and techniques, such as depressed green areas, infiltration wells, rain gardens, and infiltration trenches. Using rainfall data from Araraquara-SP and applying IDF equations, the spreadsheet proved efficient in obtaining technical and economic parameters, standing out as a decision-support instrument for sustainable planning. Practical application in Araraquara evidenced the technical and economic feasibility of CTs, especially the combination of infiltration wells and trenches, compared to the conventional alternative of a virtual detention basin. The automation of calculations reduces errors, accelerates processes, and enhances the reliability of results, making the tool a valuable contribution to resilient urban planning.

Green and blue infrastructures are being developed for stormwater management, including green roofs, permeable pavements, vegetated basins, and more. These solutions provide a wide range of benefits. First, they deliver regulation services such as infiltration, water retention, and cooling effects. Second, they offer cultural services, including landscape, leisures, and support for research and public awareness related to stormwater management and biodiversity. A website has been created to showcase these ecosystem services. It features editorial content as well as a questionnaire. The tool is organized into three sections: one outlining the project’s context, another focusing on user goals, and a third offering information on stormwater management issues. The second section guides users toward recommended solutions. It presents various types of information, such as definitions and assessments of biodiversity reservoir potential. Detailed fact sheets describing each type of infrastructure are also available.

This study applies life cycle assessment (LCA) methodology to evaluate the environmental impacts of bioretention systems through case studies in Quebec, Canada. The case studies include impervious parking lots and wide residential streets, all integrating bioretention systems for urban stormwater management. The LCA boundaries encompass materials, construction, maintenance, operation, and end-of-life phases. A key innovation of this research is the integration of functional benefits of bioretention systems, such as improved water quality, reduced peak flows, and mitigation of urban heat islands, into the LCA framework to complement the traditional impact-focused assessment. The objectives of the study are to quantify both impacts (from materials, construction, maintenance, and end-of-life) and benefits, assess data accuracy, and perform uncertainty and sensitivity analyses to address gaps, including limited performance data, inconsistencies in design parameters, and variability in maintenance practices. The findings will help optimize design and support more informed decision-making for sustainable bioretention systems.