Coastal erosion and sediment management in Portugal
27-28 October 2016, Lisbon, Portugal
Celso Aleixo Pinto, Senior Technician – Portuguese Environment Agency
About 20% of Portuguese´s sandy coastline (circa 42% of the total length of 987 km) experiences erosion, with retreat rates in some locations ranging between 6 to 8 meters per year. Since 1958 about 1220 ha (≈ area of 1700 football fields) of inland disappeared due to erosion.
Coastal erosion causes in Portugal are both natural and anthropogenic, namely: interventions at river basins (e.g. dam construction, dredging in river basins), coastal engineering structures (e.g. downdrift erosion due to presence of jetties, groins and breakwaters), sea level rise and changes in storminess and wave climate.
Damage and loss of land, property and infrastructure is widespread, increasing risk for local communities, leading to the adoption of several coastal protection measures in order to reduce the impacts of coastal erosion.
Hard structures, such as groins, breakwaters, seawalls and rock armour were extensively used during the 1970´s and 1980´s, leading to the armouring of significant parts of the Portuguese shoreline. Until a few years, the assessment of possible response strategies to coastal erosion has mainly focused on hard protection measures that, despite the positive effects to protect and mitigate risk for local communities, not managed to solve the global problem of sediment deficit. Simultaneously, there has been increasing awareness of the benefits of “soft protection” measures, such as beach nourishment, and in the last 10/15 years the number of projects and volumes placed in the nearshore, dry beach and dunes increased significantly.
About ¾ of the sediment sources for beach nourishment came from regular maintenance dredging made by Port Authorities, reinforcing the importance of this activity in coastal erosion management.
This work presents an overall perspective of coastal erosion in Portugal and protection strategies adopted. A retrospective of beach nourishment practice is shown as well as the ongoing and future strategy of coastal protection based on a recent framework of integrated sediment management policy.
Last update: 19 October 2016