Analyse multicritère des mesures de lutte contre l'érosion côtière : développement d'un outil d'aide à la prise de décision

Abstract

Measures are needed to protect the coastal facilities that are built to support the socioeconomic development of maritime regions, and are threatened by coastal erosion. However, every coastal protection measure has specific effects and consequences on coastal systems. Coastal zone management is further complicated by the diversity of interests of a multitude of stakeholders associated with socio-economic activities. In Quebec, analysis reports on coastal erosion solution focus mainly on the technical aspects, neglecting socio-economic and environmental concerns. In this situation, potential repercussions are ignored, exposing the coastal system to unknown risks. The approach use dis demonstrated by a case study, which combines both the technical and the decisionmaking components. The technical aspect was developed with data from the baie de Plaisance, Îles-de-la-Madeleine. Firstly, a description of the study site was obtained by the characterization of the coastal system. On this basis, a significant wave height of 2,280 m for a return period of 30 years was calculated. Secondly, based on their technical properties, coastal protection measures were categorized, in order to facilitate the analysis their respective characteristics. Following this exercise, a preliminary evaluation of coastal protection measures allowed the selection of intervention techniques, which were applicable to the study site and met engineering standards. The decision-making component was formalized using the Analytical Hierarchy Process (AHP), a multi-criteria analysis method. Three organizations from the Gaspe peninsula (Bonaventure, Comité ZIP Gaspésie et SCFG), were consulted. Divergence of interests between the organizations was shown in the weight acorded to the decision making criteria and in the prioritizing of coastal protection measures. In order to reduce differences, two iterations were conducted, requiring a redefinition of coastal protection measures. Following the iterations’ process, four intervention scenarios, which stood out in the ranking, were selected. A cost estimate and an efficiency indicator were then calculated to facilitate decision making. This work demonstrated the usefulness of a global approch, which broadens the basis for the decision making process in coastal zone managing. The approch could be improve by adding multidisciplinary team to identify precisely the ecological, hydrosedimentary and social parameters influencing the selecting of coastal protection measures.

Date	15 Jan 2017
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Mathias Glaus (Supervisor)