IT-FR cooperation in Heritage Science

Evolution-adaptation of coastlines in the context of climate change

Sedimentary coasts are very dynamic even without climate change or sea level changes. Their shoreline can move at rates of meters per years. If the sedimentary budget of a given coast is negative, erosion predominates and the shoreline is retreating. Conversely, if the sedimentary budget is positive, sediment accumulation predominates and the shoreline is migrating seaward. Today a major consequence of global warming is sea level rise. Global mean sea level rise accelerates since the 19^th century and reaches 3,6 mm/yr for the last decades. This trend will continue for the next centuries. The effect of sea level rise on many sedimentary coasts is a shoreward migration of the shoreline. Sediment accumulation along the coastline is the main parameter that can counteract this shoreline migration induced by sea level rise. Unfortunately, sedimentation along many coasts is reduced due to human activities, like river damming or land reclamation, leading to an increase of coastal vulnerability to flooding. In addition to global sea level rise, fast sea level rise due to storm surges can occur locally and lead to major marine flooding. The frequency of these extreme sea levels related to storms will be increased by global sea level rise. Facing these already observed and projected evolutions, many adaption strategies are proposed. Hard defences, consisting of sea walls, rock armour, groynes, etc are able to prevent shoreline migration but at the same time are expensive and usually lead to beach erosion and major perturbations of coastal ecosystems. An example of soft defence is given by beach nourishment. Massive sand supply can result in an effective coastal protection, but also strongly impact coastal ecosystems. Both hard and soft defences are costly, energy-consuming and need maintenance. Ecosystem-based solution are increasingly popular in the research community and their application on sedimentary coasts has several advantages. An example is given by protection and restauration of coastal marshes and wetlands and/or “depolderisation”. The main advantages are: (1) fast sedimentation and building up elevation to keep pace with sea-level rise; (2) limitation of extreme sea levels during storms by flooding of lowlands, (3) wave energy dissipation by vegetation; (4) increase in biodiversity and biomass; (5) increase in water quality and (6) protection of coastal natural heritage leading to improve human health and well-being, social cohesion and connection of people to nature.

Sensing the invisible for a sustainable management of underwater cultural landscape: hints from the Baia submerged archeological park

AIMS

Sensing technologies applied to different operational purposes:

1. Systematic non-invasive in situ monitoring of UCH

• Monitoring is the most effective method for studying changes to a submerged site over the course of its lifetime and for potentially identifying the factors that influence a site’s degradation so that preventative measures can be implemented.
  • In line with the main principle of the UNESCO 2001 Convention aiming to develop new ways of in situ protection

2. Simultaneous investigation of seafloor geomorphologic features and its cultural resources

• Improve the integration of archaeology and cultural heritage management within the marine science in line with the aims of
  • The Ocean Decade Heritage Network
  • The integration of UHC into Marine Spatial Planning (MPA)

3. Fruition of UCH

• Sensing technologies provide a continuous overview of the seabed morphology and associated cultural features both to diving and not diving public.
  • Underwater cultural landscapes are not human living environments and we do not see them directly and continuously.

METHOD

Very High Resolution and Ultra High Resolution echosounder systems including

• Multibeam echosounder system
  • Depth measurements for morphological and archaeological characterization and mapping
• Side Scan Sonar system
  • Seafloor acoustic reflectivity measurements for target detection and seabed composition

CASE STUDY

A pilot action is being implemented through the application of remote sensing techniques in the submerged Archaeological Park of Baia (the Roman Baiae; Naples, Italy). This area represents a unique example that combine cultural and natural heritage in marine environment. The importance of such interrelation has been formally recognized with the establishment of the Marine Protected Area (MPA) in 2002, based on the presence of marine habitats of community importance.

The Archaeological Park of Baia is part of an active volcanic complex, the Campi Flegrei caldera, which is characterized by frequent earthquakes and short-term vertical ground movements in the range of several metres to several tens of metres, known as bradyseism. Consequently, a number of architectural remains including villae maritimae and landing ports are now are presently drowned up to ca. -10 m below the actual mean sea level.

The theme of sustainability in the conservation and restoration of cultural heritage is mainly addressed to the research and testing of new organic products deriving from natural sources such as : essential oils, nanocelluloses, polysaccharides extracted from algae , bacteria for cleaning and consolidation of artworks. On the contrary equally important factors, such as the global procedures and methodologies used in restoration sites, are often not taken into consideration although they influence the sustainability of the interventions in a perhaps even greater way. This is probably due to the complex multiplicity of aspects to be evaluated. For this reason, it would be advisable to adopt green planning guidelines that favor the reduction of environmental impact. The practice of guided and sustainable planning, by quantifying the ecological impact of each operations, could in fact promote the development of an ecological project index, which can guide administrations in the choice of more sustainable interventions.