Studying Sea Level Rise Impacts in the Llobregat Delta.
The Llobregat Delta, located just south of Barcelona, is one of the most vulnerable areas in Catalonia to the impacts of sea level rise. As part of the MedSeaRise project, this area has been selected as a case study to examine the potential consequences of future sea level changes on critical infrastructure, ecosystems, and economic activity.
The Delta was chosen because it concentrates both critical infrastructure and natural heritage. It hosts major assets vital for the Catalan economy—the Port and Airport of Barcelona, regional transport corridors, and key water and energy systems. At the same time, it supports rich biodiversity, including protected wetlands and dune ecosystems that provide essential environmental services.
Rising Vulnerability
With its low elevation, proximity to the coastline, and intense urban and industrial activity, the Llobregat Delta is particularly exposed to sea level-related hazards. Past human interventions (including river canalisation, port expansion, and the loss of sediment connectivity) have further increased its vulnerability to marine flooding, erosion, and saltwater intrusion.
Focus of the Study
This case study does not propose adaptation strategies. Instead, it assesses the physical and economic consequences of sea level rise under high-end climate scenarios. Using detailed elevation data and high-resolution modelling based on a global warming level of +4 °C (99th percentile scenario), the study estimates that over 35 hectares of the delta may be permanently flooded by 2100 if no action is taken.
Key Projected Impacts
- Over 80% of the flood-prone area overlaps with port-related infrastructure, especially container terminals, cruise docks, and nautical service zones.
- The annual economic contribution at risk exceeds 2.1 billion euros, based on current and projected activity levels in key maritime and tourism sectors.
- The estimated replacement cost of exposed infrastructure is more than 110 million euros.
- Water systems, including wastewater treatment plants and groundwater protection wells, face growing challenges from sea level rise and extreme rainfall.
- Natural areas, such as protected wetlands and dunes, are increasingly affected by salinization, wave overtopping, and erosion.
- Transport corridors essential to regional mobility, such as the A-2 highway and coastal rail lines, may face increasing disruption during flood events.
These figures reflect partial disruptions and recurring economic losses, not total destruction. However, they demonstrate how even moderate sea level rise can lead to significant regional consequences when it affects areas with a high density of infrastructure and economic value.
Stakeholder Engagement
The case study is based on direct engagement with local authorities, technical departments, and infrastructure operators, including the Port de Barcelona and the Metropolitan Area of Barcelona Authority. Stakeholders helped identify specific vulnerabilities across water infrastructure, drainage, aquifer protection, and mobility systems.
They also highlighted the growing complexity introduced by new environmental regulations, such as the revised EU directive on urban wastewater treatment, which places stricter technical requirements on systems already under pressure.
Conclusion
The Llobregat Delta case study shows how sea level rise threatens both ecosystems and infrastructure. It also highlights the economic risks for regional stability. By quantifying impacts and mapping vulnerabilities, the study provides crucial evidence for informed planning and decision-making at local and regional levels.
