Maritime Forum

Interactions in the coastal areas at the local and transnational scale in a changing environment: surface waters and the subterranean estuary, sediment fluxes, erosion and transport processes, stability of the coasts.

Published on: Tue, 15/02/2011 - 16:32
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    The base reference for coastal defense is represented by long term observation of variables related to the exchange of matter and energy between the land and ocean. For the Mediterranean area, as for other European domains, coastlines and tributary systems as river catchments and acquifers are typically transnational. These observations must then be shared in a cooperative framework by the different communities. Forseveral reasons, not latest the inadequate fundings from NationalGovernments and the proliferation of provinces on coastal areas, anintegrated network of observational facilities is far from being developed and coordinated even at the local level. Just to make an example, relatedto the Italian situation, the easiest variable like river discharge ismonitored by different institutions with no coordination in themethodologies for acquisition and publication of results, which are seldom accessible to the general public as well as the scientific community. For other interesting variables, excluding the meteomarine variables, thesituation is even more complex since in some cases relevant processes are still unmonitored. A brief discussion with colleagues involved in coastal research permitted to identify some issues which can be developed on behalf of the EU.

    1. First of all: the development of an interactive database of river discharge measurements for Mediterranean tributaries, implementing real-time monitoring where this is still missing.
    2. Monitoring of suspended sediment transport in estuaries and coastal lagoons. For most of the Mediterranean catchments the intensive exploitation of the water resource for hydropower production and land irrigation dramatically changed the sediment yield with major consequences on the stability of the coasts. At present, for the Italian rivers there is no systematic monitoring of large rivers after the ‘60s preventing any evaluation of recent changes as well as prediction of future trends.
    3. Study of longshore transport of sand coupling information from fixed stations along the coast (again largely missing) to state of the art modeling approaches which are already available in several research facilities of the different countries and are already granted by many EU project fundings.
    4. Bathymetric data are fundamental information for modeling processes of wave propagation and longitudinal transport of sediments. For most of the areas, including many of those affected by intense erosion and shore retreat high resolution bathymetries are not available even though modern techniques could easily fill the gap providing the necessary knowledge.
    5. Evaluating groundwater discharge in localized points (coastal springs in karstic regions) as well as diffuse inputs (SGD, submarine groundwater discharge) along the coastline in the zone which is identified as subterranean estuary. Besides inputs, we need to better understand the deep and subsurface structure of coastal acquifers and their relation with seafloor morphology. Information on the hydrogeological characteristics of the coastal deposits (structure, permeability/transmissivity, seasonal trend in the direction of fluxes, gradients etc.) are also important.Strategic freshwater resources including those hosted in coastal and marine acquifers both at national and transnational scale must be considered.
    6. Modelling subsurface flows and exchange processes as those between surface waters and acquifers, seawater intrusion in coastal acquifers and in the area affected by salt wedge propagation in estuaries and its increase in relation to relative sea level rise, recharge, and anthropogenic factor (extractions).
    7. Simulating the process of “desertification” of coastal areas related to seawater intrusion in soils. Various components can be considered, as subsidence, eustacy, salinization of acquifers/soils, erosion of the coastline, climate changes and anthropic activities. We have many areas in the Mediterranean where this process is threatening agriculture and other economic activities