Port of Llanes, Spain (Fernández-Pérez et al., 2024)

The Port of Llanes on Spain’s North Atlantic coast faces increasing climate risks driven by sea level rise, stronger storm surges, wave agitation, and compound extreme events. To support long-term resilience, a research study applied an adaptation and pathways framework to the port’s coastal structures, equipment, and service areas. The approach assessed the port as an interconnected system, including its rubble-mound breakwater, dry dock, cranes, fish market building, and fishing and marina zones, before developing targeted adaptation strategies and pathways based on performance thresholds, risk evolution, and feasibility under different emission scenarios (RCP 4.5 and RCP 8.5).

Central to the adaptation strategy was the identification of key risks where climate impacts surpass acceptable operational and structural thresholds:

• displacement of armour units in the main breakwater
• equipment failure due to overtopping, wind, and flooding
• stoppage of service operations from wave agitation and high current velocities in the harbor basin.

These risks were derived through a probabilistic assessment of climate hazards downscaled to port level, incorporating dynamic projections of waves, winds, currents, and sea level rise for both short-term (2027-2045) and long-term (2082-2100) horizons. Synthetic multivariate extreme sea states ensured that adaptation decisions reflected the full combined intensity of future climate conditions.

Adaptation pathways were then developed by evaluating a suite of both constructive and non-constructive measures and quantifying their risk-reduction potential. For the breakwater, optimized solutions included adding or replacing armour layers with heavier 50-tonne units, which in the study met the minimum 25-year lifespan requirement for that modelled option. For port equipment, adaptation options ranged from elevating the crown-wall crest to constructing berms, strengthening equipment, or relocating vulnerable assets. The analysis showed that combinations of measures, rather than single interventions, were often necessary to achieve required performance levels, especially under high-emission futures. For service operability, the construction of a 125-meter rubble-mound revetment and selective relocation of services were identified in the study as the preferred options, performing better than early-warning systems and tugboat support, which improved navigation but did not reduce harmful basin wave agitation.

A multi-criteria assessment, integrating adaptation need fulfillment, flexibility, and cost-efficiency, was used to identify optimal pathways and implementation timing. Across all risk categories, the findings emphasized the importance of early action, with most effective measures recommended before 2030 due to unacceptable risk levels emerging as early as the 2020-2045 period. The study’s proposed pathways set out a sequence of interventions intended to remain flexible across climate scenarios, while also identifying adaptation limits and areas requiring combined or staged measures. The approach demonstrates how integrated, scenario-responsive adaption planning can support resilient port operations under escalating climate pressures, however, these are study findings for proposed options at one port, not built works or a general ranking of adaptation methods.