60 research outputs found
An Integrated Coastal Sediment Management Plan: The Example of the Tuscany Region (Italy)
This paper presents the results of a study carried out to support the Region of Tuscany Coastal Sediment Management Plan, with the main aim of establishing the sediment budget considering the time span from 1981-1985 to 2005 for the 56 coastal sectors into which the 215 km-long continental sandy coast of Tuscany (Italy) was divided. The sand stability (according to a stability index) and colour compatibility (according to the CIEL*a*b* colour space with an acceptability range conforming to national guidelines) were determined in order to assess the possibility of using the available sediment in accreting sectors to nourish the beach in eroding areas. Only in two cases-i.e., the updrift of a harbour (at Viareggio) and in a convergence zone (at Marina di Pietrasanta)-are the volumes of sufficient magnitude to support a large nourishment project; however, the mean sand size is too small to guarantee efficient nourishment, even with medium-term stability. In contrast, the colour difference, in most of the cases, was shown to be acceptable. Other small sediment stocks, suitable for colour but not for grain size, can be used for periodic ephemeral nourishment works to support seasonal tourist activities. The limited resources available make it necessary to adopt a plan for their optimal use from a regional perspective. This kind of study is of great interest for the proposal of sound management actions to counteract the increasing erosion processes linked to climate change phenomena and human effects on rivers and coastal systems
An integrated approach to coastal erosion problems in northern Tuscany (Italy): Littoral morphological evolution and cell distribution
Occupation of the coast has significantly increased in recent decades, mostly due to a greater demand for
recreation and tourism. Today, erosion threatens many human-made structures and activities, requiring an
integrated approach for the understanding of coastal dynamics and identification of alternatives to associated
problems. This study investigates a 64 km-long coastal physiographic unit in the northern microtidal littoral
of Tuscany (Italy). Vertical aerial photographs and direct field surveys were used to retrieve changes in
shoreline position over 1938–1997 and 1997–2005 time intervals. Significant beach accretion was observed
during the first period updrift of Carrara (84 m) and Viareggio (280 m) harbours and at Marina di Pietrasanta
(100 m), whereas severe erosion occurred downcoast of Carrara harbour (−130 m, at Marina dei Ronchi) and
on the northern side of Arno river mouth (−400 m). Similar trends were observed between 1997 and 2005;
beach slope between the 1997 shoreline position and the closure depth correlated well with the distribution
of erosion/accretion patterns from the 1938–1997 period (slopes were lower in eroded areas than at sites
under accretion). Longshore distribution of erosion/accretion patterns was controlled by coastal compartmentalisation.
Three of the main littoral cells were mostly formed by natural limits (i.e., Punta Bianca
promontory, Marina di Pietrasanta, the Arno river mouth and the port of Livorno). Several sub-cells were
created within these cells due to the introduction of human-made structures (such as Carrara and Viareggio
harbours), which formed artificial fixed limits that allowed the transport of sediments (exclusively fines) in
one direction only. Results will help improve the understanding of coastal processes and manage littoral
sediment transport in a sustainable manner. This will reduce the need for structural interventions, such as
breakwaters and groynes, which in the past decades prevented coastal retreat at local scale but shifted erosion
downdrift, leading to degradation of the investigated area and requiring continuous maintenance
Comments on Marine Litter in Oceans, Seas and Beaches: Characteristics and Impacts.
Marine litter is observed along shorelines, pelagic, benthic marine and lake
systems all around the globe. On beaches, litter creates aesthetic and related economic
problems because a clean beach is one of the most important characteristics of a
seaside resort required by visitors. Litter can reach the marine environment from marine
or land activities but it is estimated that 80% originates from land-based sources.
The marine-based sources of litter include all types of sea-going vessel and offshore
installations, the most abundant plastic debris in the oceans being derelict (lost or
improperly discarded) fishing gear. Most of marine litter is composed by plastics due
to their greater durability and persistence, combined with plastic rising production
and low rates of recovery. Special importance is linked to microplastics because
their ubiquity, persistence, mechanical effects on biota and the ecosystem because of
ingestion by organisms and their toxic potential. As plastics degrade they can release
toxic chemicals initially incorporated during their manufacturing or persistent organic
pollutants and heavy metals sorbed to their surfaces in the environment. Such toxins
can disrupt endocrine functions and cause harmful reproductive and developmental
effects in aquatic animals
Morphological cells in the Ragusa littoral (Sicily, Italy)
Geomorphologic information, topographic maps
(dated 1967), aerial photographs (dated 1999 and 2008), and
spatial analysis procedures were used to investigate a 90 km
long coastal sector in South Sicily (Italy). Information was
obtained on coastal erosion/accretion areas, general sediment
circulation pattern and littoral cell distribution. Human-made
structures and natural headlands constituted important artificial
limits dividing littoral in morphological cells. Ports and
harbours were observed at Scoglitti, Punta Secca, Marina di
Ragusa, Donnalucata and Pozzallo. Most of them worked as
“transit” limits which interrupted predominant, eastward directed
sedimentary transport, this way generating accretion in
updrift (west) side of mentioned structures and erosion in
downdrift (east) side. During the 1967–2008 period, about
62,000 m2 and 42,000 m2 of beach surface were respectively
formed updrift of Scoglitti and Donnalucata ports. The construction
of Pozzallo port gave rise to the formation of a
“convergent” limit which favoured large accretion
(94,000 m2) east of port structure. Most important natural
structures were observed at Punta Zafaglione, P. Braccetto
and Cava d’Aliga. The knowledge of littoral cell distribution
acquires a great importance for appropriate management of
coastal erosion processes which may be mitigated installing
by-passing systems in ports and harbours and carrying out
nourishment works in eroding areas, often located downdrift
of ports and harbours (when these structures work as transit
limits) and in central part of littoral cells (when these structures
work as convergent limits)
On the status and mechanisms of coastal erosion in Marawila Beach, Sri Lanka
Coastal erosion remains a problem in many developing countries because of a limited understating of erosion mechanisms and management. Sri Lanka is one of the countries that recognized coastal erosion management as a governmental responsibility, in 1984. Nevertheless, erosion mechanisms have not yet been fully understood. We investigate the status and mechanisms of coastal erosion using empirically collected data and various techniques, such as Geographic Information System analysis of satellite images, drone mapping, bathymetric surveys, hindcasting of wind-induced wave climate, questionnaires, and semi-structured interview surveys. We identified wave climate change, reduction in river sand supply, interruptions from previous erosion management measures, and offshore sand mining as potential causes of erosion considering sediment flux and rates of erosion. Erosion of Marawila Beach began during 2005–2010 and has been continuing ever since, due to a lack of integration in the beach and the entire sediment system. It is necessary to identify the long-term, large-scale changes in the sediment system through data collection. This study highlights the importance of an integrated coastal erosion management plan and could facilitate better coastal erosion management in Sri Lanka, as well as in other developing countries
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