Restoring an overexploited aquifer: insights from the Val di Cornia coastal aquifer (Italy)
Authors: Rossetto Rudy , Caligaris Esteban Rafael , Ercoli Laura , Barbagli Alessio , Francini Alessandra , Lazzaroni Federico , Pei Alessandra , Menonna Valentina , Masi Marco , Brilli Mirko , Benucci Claudio , Palumbo Franca , Maggiorelli Roberta , Rotelli Lorenzo , Fabbrizzi Alessandro 
Published: February 2023

While several studies deal with description and causes leading to aquifer overexploitation, relatively few face the challenge of reverting unbalanced situations. Since 60 years, intensive exploitation of groundwater of the lower Cornia valley aquifer system (Tuscany, Italy) resulted in consistent head lowering and water balance deficit, subsidence, reduction of groundwater dependent terrestrial ecosystems, and salinization of freshwater resources. There, groundwater is the only source of water for drinking, irrigation, industrial purposes and it also contributes to the water needs of the nearby Elba island. We present here the main results achieved within the EU funded LIFE REWAT project (sustainable WATer management in the lower Cornia valley through demand REduction, aquifer Recharge and river REstoration; http://www.liferewat.eu) aiming at rebalancing the water budget of the Cornia river hydrologic system by means of innovation and participatory processes.Since 2018, five demonstration measures (river restoration works; Managed Aquifer Recharge; reuse of treated wastewater for irrigation; high irrigation efficiency scheme; leakage management in water distribution systems) were built and set in operation for promoting sustainable groundwater resource management, along with capacity building and participatory actions.Results show an increase in recharge/storage of about 2.5 Mm3 per year, with noticeable effects related to the increase in natural recharge from the Cornia riverbed to the aquifer (for about 1.5 Mm3/year) due to morphological restoration works. The Managed Aquifer Recharge two-stage infiltration basin of Suvereto guaranteed an increase in recharge of about 0.5 Mm3/year. Additional storage increase is related to the reduction in leakage losses from drinking water network and thanks to a more careful use of irrigation water in farming. In about two years, thanks also to favorable hydrologic conditions, the groundwater head generally arose of about 2 to 3 m in the Cornia plain. All the technical works have been complemented by a two years long participatory process leading to the signature of The Cornia River Contract. This is a voluntary agreement among the main stakeholders to promote a shared vision on next 50 years needed actions to achieve environmental sustainability along with proper water resources management. The results achieved so far provide a clear trend towards the Cornia aquifer restoration by means of low-impact and nature-based solutions along with a large involvement of the main stakeholders in creating a shared knowledge on the value of the groundwater resource.AcknowledgementThis contribution is presented within the framework of the LIFE REWAT project. The LIFE REWAT project received funding from the European Union's Life Programme LIFE 14 ENV/IT/001290.