Effectiveness of land management measures to reduce coastal georisks, eastern Québec, Canada

Erosion and flooding are geohazards that pose a significant problem in eastern Québec, as they do throughout the world. To manage such risks, zoning to set limits on new construction projects is generally the first adaptation solution introduced in an area. However, very few studies have evaluated the effectiveness of zoning in terms of risk reduction. Offered here is a retrospective approach to evaluate the evolution of settlement in coastal areas before and during the progressive implementation of zoning laws and regulations in the Percé region of eastern Québec, Canada. It was possible to evaluate the evolution of the built environment and coastal hazards by using 6 series of aerial photographs (1934-2001) and archived processed in a GIS. The results show a significant change in coastal land use. At first land use was consistent with a fishery-based economy, and later with an economy based on the tourism industry. Such a transformation in human activity leads to changes in the typology of the built environment, and consequently to an increase in the value of buildings at risk. Due to widespread ignorance respecting the intensity of hazards and the rhythm of coastal evolution, a lack of understanding and acceptance of land management regulations, an excessive level of confidence respecting anti-erosion protective structures and conscious risk taking by property owners seeking to take advantage of the coast’s attractiveness among others for tourism purposes, the implementation of land use planning and development laws and regulations in the 1980s was not able to limit the number of buildings at risk in the coastal zone. In fact, a 133% increase in buildings at risk was observed between 1980 and 2001. Only one quarter of this increase can be attributed to the coastline’s movement caused by erosion, whereas 74% of the buildings newly at risk were new, built in a zone where building was prohibited. Poorly adapted measures that limited risks over an insufficient period were also observed. Such observations reveal a problem of governance respecting the management and prevention of natural coastal hazards. While it may be useful to redefine measures for the zoning of coastal risks with precision and based on criteria that take into account the dynamics of coastal hazards, zoning on its own is no guarantee of risk reduction. Such zoning measures must be developed and applied along with a strategy for communicating hazards and risk to all actors in the coastal zone. Due to the complexity of the problems involved, reinforcing adaptive capacities of coastal communities with respect to coastal hazards requires a process whose efficiency is ensured by close collaboration among the various actors (scientists, managers, levels of government, the general public).