Management of posidonia remains

Posidonia plays a very important role in forming beaches as live organism, but also as dead organism. The dead leaves of Posidonia are accumulated on the beach, where they attenuate the force of the waves and retain the sand of the beach against sea storms. The preservation of the beaches largely depends on the accumulation of these materials.

Also, the actual beach is made up of a mixture of sedimentary materials, remains of molluscs and crustaceans shells (most of which arrive along with the posidonia) and remains of posidonia, which form layers that retain and protect the sand and in time become degraded until forming part of the beach.

Until a few years ago, it was a common practice in the management of these remains to clear them away every year. This clearance has been carried out without adopting measures to minimise the removal of sand with the posidonia, in some cases prejudicing the beach due to loss of sediment. This posidonia mixed with sand was mostly sent to the landfill. Today we are aware of the fundamental role these natural remains play but we also know that the tourist activity, the economic mainstay of the municipality, makes it recommendable to clear these remains in the summer months. It is for this reason that for several years now a series of technical and environmental criteria are being introduced to reduce the impact of this action on the beaches and based on the following principles:

  • Only remove the posidonia in the tourist season (April to October) which permits the beaches to be clear of posidonia in the summer.
  • Carry out levelling and burial operations of posidonia in small amounts.
  • Improve operations on the beaches and machinery used to reduce the removal of sand with the posidonia to a minimum and the impact on the natural profile of the beach.
  • Store the posidonia at accumulation points so it can be sent back to the beach.
  • Return the posidonia that has been removed from the beach at the end of the season, and also recover the sand that had inevitably been extracted with the removal of posidonia. On the other hand, in time, the dead posidonia will also come to form part of the beach.

By applying this criteria we can obtain the main objective, which is to try and simulate the natural processes of the coastal dynamics and beach system to favour the maintenance and preservation of the beaches so this objective does not affect the tourist season.

The management of posidonia in the municipality of San José starts at approximately the beginning of April (before Easter) and the beaches are kept clear of posidonia until the middle or end of October (depending on the beach, the season and the weather), at which moment the remains are returned to the beach. Once the posidonia has been returned to the beach, nature is left to act. In other words, the management out of season consists of not touching the posidonia until the beginning of the next season.

The fact of not taking the posidonia to the landfill also represents an economic saving. In addition, a small part is also still used for land, yards and old houses. Obviously, apart from the management of the posidonia, the sand is also cleaned and sifted during the tourist season to remove waste and adapt its state.

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