The Ministère des Transports, de la Mobilité durable et de l’Électrification des transports (MTMDET) has undertaken the reconstruction of the Turcot interchange, a key point in the road network of the Montreal metropolitan area. WSP Canada Inc. (WSP) was mandated, among other things, to establish the pre-construction conditions and to compare them with the post-construction conditions, to ensure that the project has no negative impacts on the Montreal sewer system. WSP used PCSWMM to fulfill this mandate.
The proposed drainage system has multiple discharge points in the city sewer network, all converging toward the Saint-Pierre collector. This collector is one of the biggest and more solicited combined sewer in Montreal, with a watershed of around 6,000 ha, and already presents major capacity issues as well as many overflows to the Saint-Laurent River. WSP had to combine and adapt the detailed PCSWMM model of the proposed design with the large scale PCSWMM model of the Saint-Pierre collector furnished by the City of Montreal in order to give pertinent conclusion about the impact of the project on the piezometric line and the peak flow in the collector during major rainfall events, and on the overflow volume in an annual basis.
As part of this presentation, we will discuss how the PCSWMM model was constructed and how the different simulation scenarios were developed. We will present how we used PCSWMM to answer all the preoccupations of the different stakeholders, to demonstrate that the design meets all the requirements, and even to help the City of Montreal to reduce the overflows to the river by integrating the pumping stations to the automated intelligent system in place in Montreal.