PLUGGING THE ‘HORRIBLE’ GORGE
As the city of Trento developed over the centuries, it experienced a number of disasters caused by a single river. Over 15,000 years, the River Fersina carved its way through the crumbly limestone and clay of the surrounding landscape, eventually creating a very deep, narrow, dark and gloomy canyon called Orrido, ‘horrible’ in Italian. ‘It’s not really a place where you are relaxed,’ says Roberto Rossati, a local guide. ‘It’s more scary’. It was certainly scary for the residents of Trento, who, for centuries, would have feared that any intense rainfall or passing storms would cause the river to surge and send large rocks crashing through the canyon. Stories abound of homes, churches, mills and bridges being demolished by enormous stones. The first dam at the head of the Orrido canyon was built in 1537. Constructed using large logs, it had a very short lifespan – the beginning of a pattern that would repeat time and time again over the next three centuries. Eventually, in 1850, builders began to utilise limestone blocks, constructing a 40-metre-high artificial waterfall, designed to withstand the pressure of any rocks that were washed downstream. After a large and deadly flooding event in 1882 (which the new dam resisted relatively well), the Austrian government, which administered the region at the time, made substantial investments in flood defences across Trentino. This included the construction of a second dam, 42 metres high, to provide some extra security for the residents of Trento. After it was opened in 1886, the stretch between the two dams began to collect debris and over the following century, enough rocky material accumulated to make it effectively impossible for the first dam to fail, as there was so much pressure pushing on it from both sides. Orrido also functions as a source of hydropower and is a popular tourist attraction, with a secure new viewing platform added in 2017.