The sustainability of beach nourishments: a review of nourishment and environmental monitoring practice

摘要

Beach nourishments are a widely used method to mitigate erosion along sandy shorelines. In contrast to hard coastal protection structures, nourishments are considered as soft engineering, although little is known about the cumulative, long-term environmental effects of both marine sediment extraction and nourishment activities. Recent endeavours to sustain the marine ecosystem and research results on the environmental impact of sediment extraction and nourishment activities are driving the need for a comprehensive up-to-date review of beach nourishment practice, and to evaluate the physical and ecological sustainability of these activities. While existing reviews of nourishment practice have focused on the general design (motivation, techniques and methods, international overview of sites and volumes) as well as legal and financial aspects, this study reviews and compares not only nourishment practice but also the accompanying assessment and monitoring of environmental impacts in a number of developed countries around the world. For the study, we reviewed 205 openly-accessible coastal management strategies, legal texts, guidelines, EIA documents, websites, project reports, press releases and research publications about beach nourishments in several developed countries around the world (Germany, Denmark, the Netherlands, Belgium, Spain, UK, USA and Australia). Where information was not openly available, the responsible authorities were contacted directly. The study elaborates on the differences in coastal management strategies and legislation as well as the large dissimilarities in the EIA procedure (where applicable) for both marine sediment extraction and nourishment activities. The spatial disturbance of the marine environment that is considered a significant impact, a factor which determines the need for an Environmental Impact Assessment, varies substantially between the countries covered in this study. Combined with the large uncertainties of the long-term ecological and geomorphological impacts, these results underline the need to reconsider the sustainability of nourishments as "soft" coastal protection measures.