Studi integrati idrogeologici e geofisici per la caratterizzazione ed il monitoraggio delle falde acquifere in ambienti costieri: Esperimenti in laboratorio e applicazioni in sito

Responsabili di progetto

Enzo Rizzo, Aaron Micallef

Accordo

MALTA - SM - Science Malta

Bando

CNR/UoM biennio 2018-2019 2018-2019

Dipartimento

Scienze del sistema terra e tecnologie per l'ambiente

Area tematica

Scienze del sistema Terra e tecnologie per l'ambiente

Stato del progetto

Nuovo

Proposta di ricerca

Mediterranean coastal areas share many common features in terms of climate, water and land resources, and development issues. These include arid and semi-arid climates and limited water resources, which result in agricultural development that is limited by water availability, as well as water having a high economic and social value. Sea water intrusion is one of the major environmental problems in Mediterranean coastal areas. Coastal aquifers are vulnerable to salinisation by sea water intrusion due to over-pumping exceeding internally renewable water resources, which leads to a reduction in water quality. The Mediterranean, and particularly its islands, are the most affected due to their geographical isolation and climate.

Effective tools to detect salinisation of freshwater resources are of vital importance in the prevention of groundwater contamination. In order to predict and prevent water salinisation in coastal areas, sustainable management and continuous monitoring of water resources are needed. Detailed geological and hydrogeological information of the subsurface is necessary and is usually provided by a limited number of boreholes. However, coastal areas are often characterised by complex and dynamic hydrogeological conditions, and the interaction zones between the sea water and the fresh water coming from spring are not well constrained. Monitoring and protection of coastal groundwater, based on existing and emerging technologies, should be a main aim of the scientific community. The use of hydrogeophysical methods has been standard for many hydrogeological applications because of the electrical properties associated with the lithology and the properties of the groundwater. A combination of different hydrogeophysical approaches is the best solution for the fast characterisation of the subsoil at high resolution.

Among all geophysical techniques, the most successful methods have been the electric resistivity (ERT) and electromagnetic methods (EM), due to their sensitivity to the presence of the chlorine ion. Seismic (S) methods can also help in providing geological information about fracture zones. The conventional way of combining the information provided by these methods involves a joint interpretation of their processed data, which requires an experienced interpreter. It is also often difficult to find a geological model that satisfies all available geophysical data. Recently, different techniques have been developed to enhance the interpretation process. Most of these techniques are based on the joint inversion of the different data sets, in order to achieve a unified geological model. However, these hydrogeophysical methods produce images-models that are rarely identical, making their combined interpretation a difficult task.
The purpose of the proposed project is to identify a series of actions that can be used by the research groups to develop a comprehensive systematic methodology for the prediction and prevention of fresh water - sea water interaction in coastal areas. Fulfilling this objective requires highly interdisciplinary and collaborative research in geophysics and hydrogeology, and an integrated theoretical and experimental tool. The research activities will follow two different observation scales: laboratory and real test site. A laboratory experiment (close 1 m3 in scale) will enable the observation of sea water - fresh water interaction using a hydrogeophysical approach in a controlled environment, which will define its best use in the field. The field test site will be chosen on the coastal area of Malta, where the interaction betwen sea-water and fresh-water is an important phenomena to be monitored.
The two research teams have recently started to collaborate and define an integrated work programme on the use of geoelectrical and seismic methods for hydrogeological studies of carbonate rock close the sea (Rizzo et al., 2017). The purpose of this collaboration was to provide information on role of groundwater seepage in eroding a valley located in Gnejna Valley, along the west coast of Malta. The proposed Bilateral Project is a unique opportunity to improve the exchange of experiences between the two teams, especially from a methodological point of view, in order to provide a strong contribution towards addressing an important environmental issue in the Mediterranean region.

Obiettivi della ricerca

The project combines the expertise of the two research groups in hydrogeophysics and hydrogeology. The co-operation between these two groups offers an opportunity for the exchange of data, technical know-how and field experience. In particular, the Italian team is involved in the development of new methodologies for detection. The team has internationally-recognised expertise in hydrogeophysical applications to characterise water infiltrations at a laboratory scale through the Hydrogeosite Lab, as well as many other studies to identify and mapping water flowpaths. The Maltese team has experience in the morphological, geological and geotechnical characterication of carbonate coastal areas using a range of conceptual, field, laboratory and analytical techniques.

The main aims of the project are:
-to promote the co-operation between the two groups, and to exchange ideas and know-how in the field of hydrogeophysical prospecting and hydrogeological studies of coastal issues.
-to contribute to the methodological development of new techniques suitable to study and to monitor coastal areas on the land and in the sea.
-to develop recommendations for improving existing methodologies that are adapted to the physical conditions and logistical constraints of the study areas.
-to carry out laboratory experiments to improve the use of hydrogeophysical methodologies in the coastal area and in the sea, with the purpose of detecting and mapping fresh-water/sea-water interaction.

Ultimo aggiornamento: 18/04/2025