In situ monitoring and numerical modeling tools are essential to quantify the advantages of stormwater management infrastructures and to improve their future designs. Such infrastructures offer effective solutions for decreasing runoff volume and mitigating surface sewer overflow issues in urban environments. This paper assesses the hydraulic and hydrologic performance of a stormwater management infrastructure using numerical modeling and in situ monitoring for a water square called Place des Fleurs-de-Macadam, located in a dense urban area in Montreal, Canada. This floodable park comprises a detention pond and bioretention cells that redirect and accumulate surface water from adjacent streets, enabling water infiltration and preventing excess water from surcharging the sewer system. The performance of the water square was evaluated with a coupled 1D/2D model in PCSWMM, as well as in situ monitoring, which was carried out by a flood test on site. The associated rainfall event was a three-hour rainfall of 62 mm, equivalent to a 100-year event for this area. Results obtained by numerical modeling and in situ monitoring indicated that urban stormwater runoff can be effectively mitigated. For the tested rainfall event, simulation and in situ monitoring results showed that the water square reduced the runoff volume by 98% and delayed outflows by two hours.
Ossa et al. (Wed,) studied this question.