Coastal Dynamics and Pollution

Coastal Dynamic and Pollution

Sedimentology, Geochemistry and Numerical models are used to perform different types of studies.

This area of research is focused on three major subjects

Numerical Model
COASTAL DYMANICS
Analyzed through the use of two-dimensional and three-dimensional numerical models, it focuses on the study of hydrodynamic processes that determine the morphological variation of the seabed and the coast line, as well as the dispersion of conservative (sediment) and non-conservative variables (pathogenic bacteria);
Coastal sediment transport
SEDIMENTOLOGY
This thematic area includes studies on the evolution of beaches, coastal erosion and the radio-chronological approach to the issues of coastal transport
POLLUTION IMPUTS
GEOCHEMISTRY
This research area includes the characterization of continental inputs in relation to anthropogenic sources and sources of pollution from the coastal environment

Analysis of the possible impacts of pollutants on marine and coastal environment as a result of the accident of Costa Concordia

Following the incident of the ship Costa Concordia that took place on January 13th of 2012, LOSEM modelling group has developed mathematical models of sea currents circulation and dispersion of pollutants in order to prevent damage to marine/coastal ecosystem of Giglio Island. To simulate sea currents and dispersion of polluting material with high detail, it was used a finite elements grid that allows you to have a resolution of about 20 m near the coast and the wreck. To analyze the impacts on benthic ecosystems of Giglio Island, and in particular on Posidonia oceanica (green area in the map of the marine benthic biocenosis), the group prepared a map that shows the distribution of the main marine biocenosis. Twice a week, the modelling group sent to the General Command of the Corps of the Port Captaincies and to the Civil Defence a report with the forecasts of sea currents, the dispersion of hydrocarbons and the possible impacts on benthic biocenosis.

Analysis of possible impacts on the marine and coastal environment due to dredging along the coast of Civitavecchia

Dredging activities cause an increase of the turbidity of water column, with a consequent limitation of light penetration which is necessary for photosynthesis processes in photoautotrophic organisms (such as Posidonia oceanica represented by the green area of the figure). As shown by dispersion models results, under certain weather conditions, the fine fraction of resuspended sediment during dredging operations can influence both the coastal area (summer scenario –top figure) and the area offshore (winter scenery – bottom figure). In this case it must be evaluated the fraction that remains in suspension (blue dots), which limits the growth of plants, against that one settles on the bottom (red dots), which can cause the burial of Posidonia oceanica meadows.

Microbiological risk assessment on public health in a seaside area of Santa Marinella

Emerged and submerged barriers, that are designed and built to protect the coast from erosion, may hinder mixing between coastal and offshore waters, increasing the residence time in the water column of hazardous substances (eg. faecal coliforms) to human health. Simulation were made for two days in summer to analyze how much time pathogenic bacteria takes to halve their content in the bathing area. Because of the weak sea currents of August 22nd (top figure), the time it takes half of the bacteria to reach the open sea is around 36 hours, whereas on August 25th (bottom figure) it’s around 12 hours.

Study of the dispersion of resuspended material during the laying of an underwater power line at the landing of Punta Tramontana (Gulf of Asinara, Sardinia)

During the laying of an underwater power line, bottom sediment is resuspended, which can cause irreversible damage to Posidonia oceanica meadows found along the coast. Numerical simulations relative to the dispersion of suspended material, allow to define, at different times, the areas wherethe sediment settles on the bottom (red area) and those in which the material remains along the water column (green zone).By this way it’s possible to analyze the impact and assess the risk to marine ecosystems in the area.

Analysis of the impact of coastal structures (harbors, artificial islands and submerged barriers) on coastal dynamics

Numerical models have a key role in coastal engineering since they allow to assess the best solution for the construction of a new coastal structure. In the case of the port of Fiumicino were analyzed, from a hydrodynamic point of view, the effects produced along the adjacent coastlines by a new structure (in black). The scenario, in which wind prevailing events are represented (south-west wind and scirocco) has revealed that the port produces, in the north, a gray area (in red) with a low intensity of sea currents.

The coastline between Capo d’Anzio and Torre Astura in recent years has suffered from an increase of the erosion trend due to the enlargement of the marina of Nettuno. This situation could worsen after the construction of the new breakwater of the port of Anzio, which will result in a doubling of its initial surface. Preliminary simulations have shown that there is a strong erosion trend between Anzio and Nettuno, and that the new port of Anzio will not contribute significantly to increase the erosion because the majority of the sedimentary material directed towards the south is blocked by the port structure. The location choice (distance from the coast) and the size (number of barriers) of a coastal protection structure has to be made based on the results of mathematical models. In this case were designed submerged barriers to protect northern Lazio coastline against the erosion, since they reduce the wave energy on the shoreline and consequently they limit the transverse transport of sediment, maintaining an adequate coastal transport.

Analysis of the impact of an offshore wind farm off the coast of Gargano

During the laying of an underwater power line, bottom sediment is resuspended, which can cause irreversible damage to Posidonia oceanica meadows found along the coast. Numerical simulations relative to the dispersion of suspended material, allow to define, at different times, the areas wherethe sediment settles on the bottom (red area) and those in which the material remains along the water column (green zone).By this way it’s possible to analyze the impact and assess the risk to marine ecosystems in the area.

Study of wave energy potential along the coast of Civitavecchia

In recent years have been designed and developed a wide range of devices that produce energy by exploiting the characteristics of the waves (height and wavelength) and the processes related to wave propagation towards the coast (wave setup). To define the amount of energy available on the Italian coast were used numerical models that can identify the “hot spots" (purple area of the figure below) along the coast.