“Nothing can compensate” for Portugal’s sediment stripping
Sand that should be shoring up Portugal’s coastline is “stuck in roads and buildings”.
This is the stark truth coming out of project MarRisk, conclusions of which have been presented in Galicia today.
Lusa news agency has been talking to an investigator involved in the research who highlights one of the baseline arguments that politicians so often ‘gloss over’ when talking about rising sea levels and national ‘vulnerabilities’.
The fight by islanders to save their homes in Ria Formosa not so long ago was rooted in the relentless stripping of sand from the estuary in previous years. As many explained, “we wouldn’t be this vulnerable if they hadn’t stolen all that sand…”
Since then, other communities have been forced from their homes. And Ana Bio insists that much of the reason for coastal vulnerabilities comes down to sand that “should be on the coast” being “stuck” now in roads and buildings.
Portugal has a lack of sediment “because of dams, a lot because of constructions – there is an immense amount of sand captured now in roads, in buildings, that should be in the coastal system – and this lack of sediment is something that no interventions can compensate for”, she told Lusa.
“Ana Bio was speaking on board a boat that left the port of Vilanova de Arousa, in Galicia, Spain, to sail along the Arousa estuary, next to a measuring station for the RadarOnRaia project, also used by the MarRisk project, both co-funded by the European Union’s Interreg programme, whose annual event is taking place this week in Santiago de Compostela”, Lusa explains.
The project, which ran until 2021, consisted of “assessing risks, vulnerabilities and creating tools to mitigate the effects of climate change on the coasts of Galicia and northern Portugal, and covered practically everything,” explained the researcher from CIIMAR (Interdisciplinary Centre for Marine and Environmental Research at the University of Porto).
“From monitoring, which we want to be continuous, because we need a lot of monitoring to know what the dynamics are, to know how to feed our models, to modelling, which we need to be able to make predictions, for example, of what will happen when there are changes, and even products,” she explained.
The measurements consisted of assessments of water quality, temperature, salinity, biochemical indicators and the microbiome, and there was also “monitoring of coastal morphology”.
Regarding the nothern coastline, between Caminha and Espinho, there are “some points that are ‘hotspots’ of erosion”, such as Esposende, and “areas that are more protected”, something that depends on the type of coastline, whether it’s rockier or sandier, and the “coastal protection”, which exists more in some places and less in others.
“In general there is a regression, at least in the medium term, but there are areas that are quite stable,” she said.
In detail, in Aveiro, “one of the worst areas on the Portuguese coast, the decline in the 1960s and 1970s (when sand will have been regularly removed by contractors for construction purposes) was much worse than it is now”, but it is less serious now thanks to human maintenance”, says Bio.
Further north “it’s a bit worse now, and that’s probably because of climate change”, she admits.
“Human intervention can be beneficial to a certain extent, for example protection works, although protection works often don’t work well because they drag the problem to the coast further south. The central problem is the lack of sediment,” she reiterated, stressing that losses of €300 million have already been calculated for the coast of northern Portugal if there is no risk reduction in dune habitats.
As Ana Bio explains, following the Radar on Raia and MarRisk projects, comes CAPTA – a project “more focused on mitigation” and the reconstruction of “systems that capture carbon in order to be able to curb climate change a little”.
MarRisk and Radar on Raia totalled around €4.4 million in investment, mostly co-financed by the European Regional Development Fund (ERDF), and were supported by various institutions: the Hydrographic Institute, INESC TEC, INEGI, the Portuguese Institute for Sea and Atmosphere (IPMA), CiiMAR, the Portuguese Environment Agency (APA) and the universities of Minho, Aveiro and Porto.
Source material: LUSA