Québec City Jean Lesage International Airport – Detailed modeling of the stormwater network using PCSWMM 1D-2D and groundwater exfiltration

As part of the rehabilitation program of the Québec City Jean Lesage International Airport, Aéroport de Québec Inc. (AQi) mandated WSP Canada inc. (WSP) to analyze the current drainage system and to establish a stormwater management plan. WSP used the PCSWMM software to fulfill its mandate.

WSP used both 1D and 2D modeling to represent different elements depending on preferred output detail levels. Surface runoffs around the runways and access roads were modeled in 2D and connected to 1D elements through catch basins. Modeling was done so to verify the strict Canadian Airport Standards, which require no surface accumulation near the runways. Simulation results of known rain events matched the field observations.

Flow measurements in main ditches and conduits were used to calibrate the model. Since the bedrock is near the surface and the groundwater table level fluctuates a lot, most calibration works were done by adding “synthetic” groundwater flows to natural subcatchments. This work allowed us to clearly understand the impact of groundwater flows on the airport’s drainage network.

As part of this presentation, we will discuss the project and the PCSWMM model. We will present how using 2D modeling and groundwater exfiltration allowed us to build an accurate model.