The Mar Menor is a hypersaline coastal lagoon of 135 Km2 in surface area, located at the SE of the Iberian Peninsula, between the parallels 37º 38’ and 37º 50’ North latitude and the meridians 0º 43’ and 0º 57’ West longitude. The mean depth is 3 to 4 m, and the maximum depth is over 6 m. Such characteristics made the Mare Menor one of the bigger coastal lagoons from Europe and the Mediterranean. A sandy bar, called La Manga with 22 km of long, acts as a barrier between the lagoon and the Mediterranean Sea. It is crossed by five, more or less functional, channels or “golas”. (Perez-Ruzafa, 1996).
Erosion factors include mainly natural driving forces - winds, storms, waves and a rise in sea level. La Manga was created by marine currents and the effect of the wind and waves. The wind is the main factor influencing sediment transport in this area. Prevailing winds in the area are from the East component. The modification of the sea level will lead to important consequences for low coasts such as the Mar Menor, in which the backward movement of the coast is ranked at around a meter per centimetre of rise in sea level. (Mas, 1994).
The Mar Menor lagoon is an accumulation coast dominated by sedimentation rather than erosion, although in some specific places erosive phenomena are quite evident, emphasizing the full exterior of La Manga. The main erosion causes are land urbanization on dune system, updrift construction of the San Pedro del Pinatar Port (1954) and enlargement of the El Estacio channel for the construction of a harbour. In relation to human occupation, the Mar Menor has experienced varying changes over the last 40 years. From being a practically uninhabited place, with only a few families of fishermen living permanently on its shores, there is now a large human presence, above all in the months of summer.
Since ancient times, the Mar Menor has been an economic source and has been subjected to continuous transformations. The human activities developed close to the lagoon include: salt mining, agriculture, fishery, industry, tourism and recreation, urbanisation and military uses. This conjunction of many interests and uses made the Mar Menor the target of all type of aggressions during its recent history (land reclamation, the opening or deepening and extending channels, mining, urban and agricultural wastes, urban development, building sporting harbours, artificial beaches creation, etc) (Pérez-Ruzafa, 1996).
There is no a real, active policy concerning coastal erosion. Regarding the few interventions performed (beach nourishment and construction of groins), the main policy option has been to “Hold the Line”, as promoted by public administration, commonly on a national level. It is important to point out that most of the nourishment performed on the continental shore of the Mar Menor is aimed at the creation of new beaches in a place where there was originally no morphology of sandy beaches. The main goal of these interventions was to try to attract more tourism.