Shoreline Evolution And Protection Strategies Along The Tuscany Coastline, Italy

Natural and human-induced influences on short term shoreline change and long term coastal evolution can be variable over a wide range of different temporal and spatial scales. The importance of assessing, either quantitatively or qualitatively, these causes or factors in coastal processes is paramount to the design and implementation of integrated coastal zone management strategies. This is especially true as contemporary erosion threatens to become a major environmental hazard in the absence of unified coastal defence strategies for protecting long stretches of coast as a whole ( and , 2002). In many cases defence designs have been implemented without any a priori knowledge of the 'local' or 'regional' processes operating in the area. The identification of time-averaged littoral processes can greatly impact management decisions. Identifying the major points of sediment input into the coastal unit and related littoral cell dynamics is vital to understanding the potential impact and performance of any defence strategies. Each littoral cell contains a coherent trend of littoral transportation and sedimentation, including sources and sinks and transport paths ( ., 2002). In many cases it is predicted that existing knowledge of these coastal units would greatly affect management and planning decisions. This paper details the results of recent coastal process studies along the Tuscany coastline in Italy, and elucidates the influence of human interventions along the coast on littoral dynamics and subsequent shoreline evolution. These areas have experienced severe contemporary beach erosion since the latter part of the last century. The longshore component of the littoral sediment budget has been dramatically affected by building of coastal infrastructure such as harbours, and changes in land use in the river basins. Mitigation techniques have traditionally relied on engineered coastal defences such as groins, breakwaters and seawalls. In many cases these structures exacerbate the problem both locally (increase in energy from reflected waves expedite the removal of sediment) and regionally (the removal of nearshore alongshore sediment from the sediment budget). Further, these structures usually result in the loss of dry beach area in the immediate vicinity. The shoreline configuration of these areas has been altered to a state where the length of engineering structures equals (or, in many cases, exceeds) the length of protected shoreline. The incremental costs of construction of new structures in downdrift areas and the annual maintenance costs to ensure structure stability and integrity retract from the cost-benefits of implementing these schemes. More so, although these constructions support short term objectives of protection, they fail to rectify the initial problem of shoreline erosion vis a vis the imbalance between the supply of sediment input and the volume of sediment being removed. ELASMAR WHITE