Évaluation de mesures d’adaptation aux inondations avec PCSWMM et PROMETHEE pour un très petit bassin versant

Abstract

Floods are of major concerns as they constitute a hazard for inhabitants of riparian area. Small watersheds are not spared by this problematic and often the communities living there do not have the resources to address it. Therefore, the aim of this study is to develop a methodology to evaluate different adaptation measures for a municipality at the head of an ungauged small watershed subject to floods. To do so, a very detailed hydrologic and a hydraulic model that suits the territory was designed using the PCSWMM software. This model was calibrated and validated using selected events from a one-year monitoring of water level. The model was then used to test the adaptation measures in a climate change context to better assess their resilience in a future climate. The results of the model show that the lowering of the Boyer culvert and the downstream reprofiling of the river make it possible to reduce the water level in the village section of Saint-Isidore since this cause a permanent retention of water. With all these measures, a multi-criteria decision analysis (MCDA) with the PROMETHEE method considering socio-economic, environmental and technic criteria was performed. The MCDA approach aims to prioritize the measures according to the preferences of the onsite decision makers and support the thinking involved with the decision-making process. This process allowed to guide the municipality towards measures both resilient to climate change and adapted to the decision makers preferences. Indeed, the multicriteria analysis indicates that the disconnection of the gutters and the retention basin make it possible to meet the criteria and preferences. This study allowed to pinpoint data needed to conduct a flood study in a small and ungauged watershed. In addition, it allowed to develop a robust method to include the preferences of decision makers with the use of a MCDA with measures prioritization.

Date	6 Oct 2021
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Annie Poulin (Supervisor) & Mathias Glaus (Co-supervisor)