D2.1 Good practice criteria for multi-hazard forecasting (including a multidisciplinary calibration) and application limits, as enablers for risk reduction through restoration, exportable to other coasts

The REST-COAST project (Large-scale RESToration of COASTal ecosystems through rivers to sea connectivity) is a Horizon 2020 research initiative funded by the European Commission under Grant Agreement No. 101037097. Its overarching aim is to restore coastal ecosystems across Europe by advancing science-based approaches to hazard mitigation and resilience, with a strong emphasis on nature-based solutions (NbS) and the sustainable delivery of ecosystem services (ESS). To meet this objective, the project adopts a multidisciplinary approach that combines modelling, monitoring, restoration, governance, and finance. Scientific development is tightly linked to practical implementation through a network of pilot sites representing diverse coastal typologies and pressures. These sites serve as laboratories for testing and validating coupled hydro-morpho-eco models capable of simulating the role of natural ecosystems in reducing risks such as coastal flooding, erosion, and saline intrusion. This deliverable, D2.1, documents the modelling work conducted under Task 2.1, focusing on present-day storm conditions. It presents the model configurations, validation procedures, and simulation outcomes used to evaluate the risk reduction potential of NbS across seven pilot sites. The work includes detailed analysis of hydrodynamic and morphodynamic processes, sediment transport, and vegetation interactions, as well as the derivation of site-specific ESS indicators. The models are tailored to local physical settings and restoration goals, and have been validated against real storm events using field and remote sensing data. D2.1 provides a robust technical foundation for assessing the effectiveness and operational relevance of ecosystem-based approaches to coastal risk management. The methods and results presented here contribute to the broader REST-COAST objective of supporting adaptive, transferable, and evidence-based coastal restoration strategies throughout Europe.