ENEA “finds” fresh groundwater in small islands to limit tankers
2/7/2020
Study in Favignana shows the possibility to meet residents’ water needs up to five times over
Assessing quantity and quality of groundwater in small islands and make it immediately usable in a sustainable way by the population during droughts or in case of great tourist pressure is now possible thanks to a study conducted by ENEA in Favignana, in the Egadi archipelago in Sicily.
Through hydrogeological, precipitation and temperature rates measurements and chemical analyses of groundwater, the island's water reserves were assessed and the ones with better quality or, on the contrary, more exposed to the risk of salinisation by seawater intrusion, identified.
"The capability of determining the amount of water that infiltrates the subsoil by feeding the aquifers is an important added value. The method we used in Favignana can be replicated in other contexts and in the small islands the impact of these insights can be significant both from a social and economic point of view ", continues Cappucci.
"It’s a hydrogeological balance which, just like an economic balance sheet, allows to estimate cash inflows, that is the infiltrations, and outflows, that is water consumption and loss of the island of Favignana, which was chosen for its climatic and geomorphological characteristics and the great tourist pressure in summer, " ENEA researcher Sergio Cappucci who coordinated the study, explained.
Fresh water, which does not evaporate as a result of rainfall and infiltrates underground, floats above salt water because it is less dense and, consequently, pushes more in depth the less suitable waters to be used for civil or irrigation purposes.
"The capability of determining the amount of water that infiltrates the subsoil and feeds the aquifers is an important added value. The method we used in Favignana can be replicated in other contexts and in small islands its impact can be significant both from a social and economic viewpoint ", Cappucci continued.
The communities of the islands have always known how to manage the island’s groundwater resource, developing techniques to collect and preserve rainwater, but growing tourist pressure has made it necessary to find an external supply over time, resorting mainly to tankers, given the costs and technical difficulties of creating desalination plants or underwater pipelines to bring fresh water from the mainland.
"Our study leads to the conclusion that, through a sustainable use of properly placed wells, the water needs of the resident population during droughts could be widely satisfied, limiting the use of tankers during summer," the ENEA researcher Marco Proposito, co-author of the study, explained.
"Assuming a per capita consumption of about 200 liters per day, our study found that potentially drinking water could meet the needs of about 20,000 people, less than the 60,000 of the daily summer peaks, but many more than the 3500 residents” Proposito concluded.
The Mediterranean basin is one of the areas most subject to the impact of climate change, with significant variations in both temperatures and rainfall. A study published in 2018 on Nature Climate Change showed that in the entire Mediterranean region, temperatures increased on average by 1.4 ° C compared to the pre-industrial era and by 0.4 °C compared to global averages, with a reduction in summer rainfall in some areas estimated at 10-30%.
- Field measurement of the main chemical-physical parameters of the groundwater and sample collection
For more information please contact:
Sergio Cappucci, ENEA - Technologies for Structural Dynamics and Prevention of Seismic and Hydrogeological Risk Laboratory, sergio.cappucci@enea.it
Marco Proposito, ENEA - Observations and Measures for Climate and the Environment Laboratory , marco.proposito@enea.it