Florence has completed a major flood protection programme designed to defend the city against future flooding of the Arno, 60 years after the devastating 1966 disaster.
The final intervention, unveiled on October 1 on lungarno degli Acciaiuoli, completes a system of measures covering more than 4.5 kilometres of urban riverbanks, designed to protect the historic centre and improve the city’s ability to respond to high-water events.
Funded with around 15 million euro from Italy’s National Recovery and Resilience Plan (PNRR), the project is one of the most significant recent investments in Florence’s flood defences.
“This is the solemn moment of a crucial intervention that, 60 years after the flood, finally puts the city of Florence and its extraordinary historic and cultural heritage in greater safety,” said Tuscany regional president Eugenio Giani, who presented the works alongside Florence councillor for civil protection Laura Sparavigna, Florence’s superintendent for archaeology, fine arts and landscape Antonella Ranaldi, and representatives of the civil protection and civil engineering authorities.
The investment forms part of a wider strategy that also includes flood control infrastructure upstream of Florence, including the expansion basins planned at Figline. The work combines new embankments, permanent containment structures, parapets and weathering steel protection systems with temporary barriers along some of the city’s historic riverfronts. The aim is to improve flood protection without permanently altering Florence’s most recognizable riverside landscapes.
The measures introduced along lungarno delle Grazie, lungarno degli Acciaiuoli and lungarno Generale Diaz are particularly important, where removable barriers known as panconi can be installed when significant flooding is forecast. The system relies on advances in meteorological and hydrological monitoring, which can now identify a potentially sizeable rise in the Arno with an estimated 24 to 36 hours’ warning. Once activated, Florence’s regional and local civil protection teams can install the temporary structures in less than eight hours.
Removable barriers for historic riverbanks
The newly completed system on lungarno degli Acciaiuoli covers approximately 230 metres and uses modular barriers measuring two metres by 70 centimetres. These are installed only when river levels require their activation. On lungarno delle Grazie, around 270 metres of riverbank have been equipped for protection. Here, two-metre-by-one-metre modular barriers are used with a system of braces installed upstream of the bridge to withstand the perpendicular pressure exerted by floodwater. On lungarno Diaz, the intervention covers approximately 175 metres. The existing elevations already provide the required hydraulic closure, meaning that removable barriers are not needed. Instead, the watertight gate at the Canottieri access point has been upgraded to ensure continuity of the flood defence system.
The approach is intended to balance hydraulic safety with the preservation of Florence’s architectural and landscape heritage. Rather than permanently enclosing the historic lungarni behind additional structures, the removable barriers remain out of sight until they are needed.
“The works inaugurated today demonstrate a profound change in the approach to flood safety,” said Bernard Dika, undersecretary to the presidency of the Tuscany Region. “It is no longer simply a question of building permanent defences, but of integrating infrastructure, forecasting capacity, planning and civil protection organization into a single risk-management system.”
For Florence councillor Laura Sparavigna, the project is particularly significant in the year marking the 60th anniversary of the 1966 flood. “It is a concrete and serious way of taking care of our citizens and our community,” she said, noting that the wider project addresses stretches of both banks of the Arno. “We have learned the lesson of 60 years ago and must continue to work day by day, through information and structural investment.”
The new defences also form part of a broader flood management system involving the Bilancino reservoir in the Mugello and the Arno’s flood expansion basins. Together, the measures are designed to allow water flows of up to 3,500 cubic metres per second to pass safely beneath the arches of the Ponte Vecchio.
Further protection is expected when the expansion basins at Figline are completed.
Sixty years after the Arno flooded Florence, the latest works mark a shift from simply responding to disasters to anticipating them, combining engineering, forecasting and emergency planning to protect the people who live along the river and the historic landscape that surrounds it.
