Erosion and use of the coast in the northern Sardinia (Italy)

摘要

The study provides an overview of coastal erosion of northern Sardinia, indicating the causes and the effects of the most relevant and identifies critical areas to the possible scenarios of extreme events. The knowledge of the state of natural balance of the coasts is essential for planning and protection in the medium-long term and requires careful evaluation of the risks and potential dangers, obtainable through geomorphological, sedirhentological and meteomarine data interpretation, and degree and the human settlement type. Many of Sardinians waterways are torrential and have poor solids discharges due to existence of the dams, was 393 (56 large reservoirs and 336 small reservoirs) that remove sediment to natural beach nourishment. It is enough to calculate the volume of sediment trapped from the reservoir to have a phenomenon dimension, total 4,372,933.5 m~3 for Cedrino in use from 1989 to 1,085,700.0 m~3 for Cixerri in activity since 1992 and 2498.226,2 m~3 for Bidighinzu in use since 1959. An interference with such significant contributions to the sea involves a sedimentary deficit in the system which leads to an inevitable retreat of shorelines. For the evaluation of the areas with greater sensitivity and vulnerability, it is over considered the human load resulting from the infrastructure presence and activities along the coast and next to the river banks. It has also been decided through a questionnaire meant to assess the value of an environmental asset (in this case a stretch of coastline) which is understood as a "sense of well received" by the people, because it has become clear that the remediation or enhancement cannot be delegated to a mere technical-scientific approach but there has to be shared with the community. The integrated analysis of these factors helped to identify critical situations and vulnerabilities along the coasts of Northern Sardinia that led to the mapping of areas at risk.