Successful rehabilitation of a sand dune system

摘要

The construction of an underwater effluent damaged the continuity of the Leirosa sand dune system, which is located at south of Figueira da Foz, midway along the Portuguese coast. The use of heavy machinery in this fragile area has worsened the erosive effect already caused by an existing groyne one kilometre north of the affected area, The recovery of this system started in 2000, with the artificial reconstruction of the dunes followed by replanting. In February 2001, however, during a storm whose impact was felt all over the central area of Portugal, and especially on the coast, the oceanic front of the Leirosa dune system was destroyed, and alternative hard protection devices have been encouraged. The study carried out showed that a submerged breakwater could be an interesting and efficient strategy, not only to protect the coastal system, but also to increase recreational beach activities. However, the costs involved and the time required to implement this solution have been considered insupportable and, as a consequence, the local industries involved decided on another solution. Geotextiles have been successfully used in hydraulic engineering and more recently also in the construction of artificial dunes and stabilisation of beach nourishment measurements. It is shown that the use of geotextiles can be as effective as any so called "hard engineering protection", with the advantage of being adaptable to the morphology of the dune system and using locally available sand.