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. Keywords: sand dunes, coastal protection, submerged breakwaters, geotextiles.
IntroductionIn general, the coasts are nowadays hugely popular places to go for holidays or a day out. Residents and visitors alike are attracted by the sandy beaches, striking scenery and the chance to 'get away from it all'. They provide limitless scope to watch wildlife, pursue outdoor sports such as diving and sailing, or simply walk, contemplate and seek inspiration.Unfortunately, massive tourist use of many beaches has been followed by the destruction of many coastal dune areas in recent decades all over the world. Reconstruction of destroyed dunes is nearly impossible because many of these zones have been taken over by resorts, or in some other cases, the new dunes are smaller and more linear than the natural dunes they have replaced.It is to everyone's benefit to maintain the qualities that make the coasts such special places -their beauty, diversity and wildness. Visitor pressure alone can severely damage the natural environment of these coasts. Too much trampling encourages dune erosion. Beaches may be spoilt by litter and sewage. In general, coastlines are fragile environments and we need to be aware of the impact our own activities may have. This is vital if we are to conserve the quality of our coastlines and ensure that they can be enjoyed by many generations to come.In many coastal zones, it is not uncommon for sand or shingle to be taken from beaches or dunes. This may be used for anything from building to the filling of bunkers on golf cour...