A multi-criteria framework for prioritizing urban flood adaptation strategies under a standardized investment: an approach based on PCSWMM and PROMETHEE II
Melanie McGrory, Francis Marleau Donais, Jean-Luc MartelABSTRACT
Diagram summarizing the study methodology. Eight stormwater management alternatives were hydraulically simulated using PCSWMM under a standardized $1 million investment, evaluated with PROMETHEE II across 14 quantitative and qualitative criteria, and ranked according to their net flow. Nature‑based solutions provide the greatest overall value.
Traditional drainage infrastructures were not designed to manage the increasing intensity and frequency of rainfall events caused by climate change, prompting municipalities to seek investment strategies that deliver the best value at the watershed scale. This study evaluates and ranks eight stormwater adaptation strategies under an equivalent 1M CAD$ investment scenario to support municipal decision-making. A multi-criteria decision-making framework is developed to compare grey and blue–green stormwater strategies across 14 technical, environmental, financial, and social criteria. Hydraulic performance was simulated using a calibrated Personal Computer Stormwater Management Model (PCSWMM) of a 5.35 km2 urban watershed in Montreal, Canada. The novelty lies in integrating a standardized investment constraint at a watershed scale, in a simulation-based multi-criteria decision analysis framework, allowing direct comparison on a common economic basis. The eight evaluated options are oversized pipes, underground chambers, permeable pavers, blue roofs, green roofs, rain gardens, bioretention systems, and sponge parks. The Preference Ranking Organization Method for Enrichment Evaluations II (PROMETHEE II) multi-criteria approach was used to determine the overall value of each strategy. Results show that bioretention, sponge parks, and rain gardens achieve the highest rankings, all dimensions considered, while oversized pipes rank lowest. The proposed framework offers an adaptable tool to support municipal planning and investment decisions.