## 5 Conclusions  
Concluding, despite the limitations of the data time series, the present study demonstrated how local conditions interact with meteo-ocean conditions in shaping local morpho-sedimentary dynamics, stressing the need for local approaches to monitoring and erosion risk analyses. Dynamics varied markedly in space, with patterns depending on beach type and exposure, as well as on the presence of coastal defence structures that alter local hydrodynamics and, therefore, sediment transport and deposition.  
The analysed coastal stretch suffered an average 1.6 m retreat of its shoreline in a decade with a slight increase in its volume (0.6%). However, analyses of shorter periods (annual and five years) revealed greater shoreline retreat and sediment budget values, demonstrating the high temporal dynamics of this coastal stretch and stressing the need for longer monitoring periods (more than 10 years) to assess the main trends of coastal morphodynamics.  
Although the studied stretch seemed to be rather stable in the medium term (decade), the northwest coast of Portugal has been suffering from a scarce sediment input and a high-energy wave climate, which turns this coast into one of the most active in terms of sediment transport fluxes. If a projected mean sea-level rise of the order of 1 m by 2100 is confirmed, shoreline retreat will become a major problem in the next few decades.  
Coastal management should therefore be based on structural monitoring programs, with surveys at adequate temporal and spatial scales to understand local dynamics and to be able to apply adequate erosion mitigation measures in the right places. Furthermore, given that many coastal systems show sediment deficits, mainly due to anthropogenic interventions in rivers, such as dams, and sediment extraction, sediment budgets should play a central role in the development of coastal defence strategies.  
Conceptualization, H.G., J.P. and A.B.; methodology, A.B., J.A.G. and J.P.; software, J.A.G. and A.B.; validation, J.A.G.; formal analysis, J.A.G., A.B. and IL; investigation, H.G., J.P., J.A.G., A.B. and IL; resources, H.G., J.P. and J.A.G.; data curation, J.A.G.; writing--original draft preparation, A.B.; writing--review and editing, A.B., J.A.G., I.I., H.G., J.P. and L.B.; visualization, A.B.; supervision, L.B.; project administration, H.G., J.P., L.B. and A.B.; funding acquisition, H.G., J.P., L.B. and A.B. All authors have read and agreed to the published version of the manuscript.  
This research was partially supported by the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 through national funds provided by the FCT--Foundation for Science and Technology and European Regional Development Fund (ERDF). This work was further funded by the projects ATLANTIDA (ref. NORTE-01-0145-FEDER-000040) and Ocean3R (ref. NORTE-01-0145-FEDER-000064), both of which were supported by the North Portugal Regional Operational Programme (NORTE2020) under the PORTUGAL 2020 Partnership Agreement and through the European Regional Development Fund (ERDF).  
Not applicable.  
Data were supplied by the European Union MarRISK project: Adaptacion costera ante el Cambio Climatico: conocer los risegos y aumentar la resilienta (0262_MarRISK_1_E) through EP INTERREG V A Espana-Portugal (POCTEP) program and the project INNOVMAR-Innovation and Sustainability in the Management and Exploitation of Marine Resources (NORTE-01-0145-FEDER000035, within Research Line ECOSERVICES), supported by NORTE 2020, under the PORTUGAL 2020 Partnership Agreement, through the ERDF.