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How can episodes of strong waves, caused by climate change and rising sea levels, affect promenades? This is what Corrado Altomare, Ramón y Cajal researcher at the Maritime Engineering Laboratory of the UPC, has proposed.
Rigid constructions built at the end of sandy beaches, especially vulnerable to rising sea levels and extreme waves caused by climate change. These are the maritime passages that we find on the Catalan coast and in the east of the peninsula: structures that are increasingly exposed to possible floods and extreme weather phenomena.
“The boardwalks were designed in a completely different scenario than today. Now, with climate change, storms like Gloria will be more frequent and intense. We must have a tool that allows us to prevent the consequences of these situations - the flow of water that passes over a coastal structure - and whether it can put people and properties at risk," explains Corrado Altomare, Ramón y Cajal researcher at the Laboratory of Maritime Engineering (LIM) from the UPC. This is the objective of OVERPROET (Semi-empirical model of ware OVERtopping of seafront PROmenades with Emergent Toe), the research project for which Altomare, who is a professor at the Higher Technical School of Civil Engineering, Canals and Ports of Barcelona ( ETSECPB), will study how episodes of strong waves can affect seafront promenades and will develop prediction models for the overtaking of this wave under different climatic scenarios, to increase the safety of infrastructure and reduce possible risks for citizens.
Experiments in the wave channel
“The boardwalks on the peninsular coast are, in the vast majority, concrete structures that have, at their feet, a beach. These are very complex systems and we must study how they are composed in different scenarios, including extreme episodes,” explains Altomare. To develop this study, first, physical tests will be carried out in the Maritime Research and Experimentation Channel (CIEM) of the LIM, which is part of the MAEHIS (Maritime Aggregated Research Hydraulic Infrastructures) research infrastructure of the Ministry of Science and Innovation.
The experts are based on real cases, details the researcher: "IN the wave channel, experimental tests will be carried out with a geometry close to that of a promenade on the Catalan coast." These experimental results will be combined with numerical simulations, using the DualSPHysics particle model, which allow the results to be adapted to different scenarios, “to cover the range of cases that may occur on the Spanish coast,” he adds. Finally, using advanced polynomial regression techniques, semi-empirical formulations will be carried out to calculate wave overshoot for this type of infrastructure.
In this way, the important gap in the state of the art in this field will be covered. And so far, no models have been developed to study and predict the consequences of extreme weather phenomena on this type of construction.
Rising sea levels, one of the effects of climate change
The seas and oceans absorb most of the heat generated by global warming. Sea level rise has accelerated in recent decades as a result of greater melting of ice in the planet's polar regions. The latest data from the World Meteorological Organization shows that the global median sea level has reached a new record in 2021, with the average rising by 4.5 millimeters per year during the period from 2013 to 2021.
In the Special Report on the Ocean and the Cryosphere in a Changing Climate, prepared by the Intergovernmental Panel on Climate Change (IPCC), it warns that, between now and 2100, sea level could register a rise of approximately , between 30 and 60 centimeters, even achieving a drastic reduction in greenhouse gas emissions and keeping global warming well below two degrees. If emissions continue to increase strongly, the rise in the level of water could range between 60 centimeters and one meter ten.
A study, led by the Spanish Institute of Oceanography (IEO-CSIC), recently warned that the rate at which sea level rises in Spain has doubled in the last 20 years: while this increase was 1.6 millimeters per year from 1948 to 2019, as of 2019 the rate at which it increases is 2.8 millimeters per year, almost double.
