Stormwater Management using Sponge Parks in the City of Montreal: A Case Study of the Prieur Park

With the increase in frequency and intensity of extreme rainfall events due to climate change, existing drainage systems are under growing strain. Not only are they degrading due to aging, but their original design conditions make them particularly vulnerable to extreme rainfall events. In this context, the City of Montreal has been actively promoting the construction of blue and green infrastructure to reduce the stress on its drainage systems. One such strategy involves rehabilitating existing parks into sponge parks, which function as retention basins while allowing evaporation and infiltration of stormwater. However, as a relatively recent stormwater management approach, best practices for optimizing their design and construction remain largely unexplored. This study aims to address this gap by analysing the performance of one of these sponge parks in Montreal.

Prieur Park, located in the Ahuntsic-Cartierville borough, was partially redeveloped in the summer of 2023 as a part of a road rehabilitation project. Specific modifications were implemented to channel runoff into the park, where it is temporarily stored during extreme rainfall events. This research employs PCSWMM 2D to model the park’s hydrological behaviour before and after the modifications, assessing its effectiveness in stormwater retention. The installation of a rain gauge and piezometers, paired with visual observations, were used to calibrate the model, while a drone survey provided highresolution topographical data.

Preliminary results indicate that the park effectively stores substantial volumes of stormwater during extreme rainfall events, including the Debby storm of August 2024, with the minimal structural intervention that were implemented in the summer of 2023. However, modelling suggests that incorporating additional bioretention cells within the park and at its entrances would further enhance stormwater retention, infiltration while mitigating the erosion issues currently observed. This presentation will also provide best practices on modelling an existing park using PCSWMM 2D to optimize its design

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