Cost-benefit analysis of artificial nourishments: Discussion of climate change adaptation pathways at Ovar (Aveiro, Portugal)

The Ovar coastline, located on the western coast of Portugal, is renowned for being one of the most erosion-prone and vulnerable areas in the country. Addressing the significant challenges faced by local communities requires the development of modern coastal adaptation strategies that encompass social, environmental, and economic factors. In this study, a participatory approach was employed to establish Climate Change Adaptation Pathways for the period between 2020 and 2100. The majority of the scenarios examined prioritize artificial nourishments, which are increasingly being acknowledged as a vital solution for mitigating coastal erosion worldwide. However, the effectiveness and durability of these measures rely on various design parameters, including placement location, frequency, volume, initiation, and the presence or absence of coastal works, among others. This research presents the primary findings of 12 scenarios simulated using the Long-Term Configuration (LTC) model and cost-benefit analysis using the COAST tool in combination with local ecosystem service value estimates (using meta-analytic function transfer) to take into account environmental benefits. This analysis aims to assess the physical and economic performance of artificial nourishments by examining the efficacy of different scenarios in mitigating coastal erosion, ultimately supporting decision-making processes related to coastal planning and management. The results highlight the intricate factors involved in determining the optimal nourishment option, which depends on aspects such as site-specific conditions, land uses and ecosystems services, and the main objectives of the intervention.