Coastal erosion is a problem that affects, with different intensities, a large part of the beaches in the world. The causes of erosion are varied, but, in global terms, human modifications to the environment and variations in physical forcing (often associated with climate change) are the main culprits. These factors cause the reduction of the contributions of sand to the coast, increase the capacity of transport of sediment in the coast and limit the availability of sediment and the adaptation of the beaches due to the urban occupation of the emerged zones. As a result, there is a negative sedimentary balance, that is, Sediment outflows from a given stretch of coastline are greater than arrivals and beach erosion occurs.
One of the most widely used methods to combat coastal erosion is artificial regeneration, which consists of contributing sediments from other places to an eroding beach so that it recovers its previous configuration and allows it to perform all its functions (protection, natural and recreational environment). ). Unfortunately, with artificial regenerations it happens as with our current account, in which if we have fixed expenses we must enter money periodically so as not to stay in the red. In the case of many beaches, the escape of sediments due to waves, currents or wind has to be compensated periodically with a new regeneration.
Artificial regeneration does not solve the erosion problem and its effectiveness has an expiration date, so it must be considered as a repeated action over time. However, artificial regeneration has been and will continue to be a fundamental tool in coastal management for the next decades due to the fact that it is a ‘natural’ method that recovers all the functions of the beach compared to other alternatives structural, that modify the ecological conditions in an irreversible way. The demand for sand will continue to increase in the near future because more and more beaches will be eroding and, in addition, more will be needed to compensate for the rise in sea level. The use of artificial regeneration will be limited by the availability of sands with suitable characteristics to be used.
So, is the artificial regeneration of beaches sustainable in the medium-long term? In Catalonia, the first artificial regenerations were made on the Maresme beaches in the mid-1980s. and since then they have been spilled on the Catalan beaches of the order of 30 million cubic meters of sand, mostly from sands located on the seabed. Among the sources of sand there is a small proportion that we could describe as ‘renewable’, which are sands that accumulate in the north breakwater of the ports, or in their mouths or in areas where sediment is retained. These accumulation zones can be recovered after a while and reused again.
Related news
On the other hand, there are continental shelf sand depositswhich are non-renewable resources that correspond to sediments accumulated thousands of years ago. Until now, only the deposits closest to the coast have been exploited, but probably In the immediate future, more distant sediments begin to be extracted, at a depth of more than 60 m.. However, the total volume of sand available on the continental shelf is limited (and its extraction is increasingly expensive), and coastal management is based fundamentally on the artificial regeneration of beaches (as is the case, for example, in the Netherlands). it is unfeasible in Catalonia to face the challenges of coastal adaptation in the future.
Definitely, artificial regeneration will be necessary and useful on certain beaches, but it is not a panacea that will solve all the problems, but must be accompanied by other territorial planning measures, coastal protection alternatives and, especially, the management of hydrographic basins to increase the arrival of sediment in the marine environment.