When the amateur photographer Alessio Bonin had a few hours to spare one afternoon in late March, he decided to venture to a nature reserve in Gualtieri, an Italian town on the banks of the Po River in Emilia-Romagna.
The drought that had been blighting the country’s longest waterway since one of its driest winters was showing no sign of easing.
The 450-mile (650km) Po flows from the Alps in the north-west, nourishing several Italian regions before entering the Adriatic. But unusually low water levels had transformed it, affecting everything from the production of tomatoes and watermelons to hydroelectric power, drinking water, commercial shipping and fishing.
It was the startling image, captured by Bonin’s drone, of a 50-metre cargo boat sunk during the second world war emerging from its watery grave that brought home the gravity of the drought to those living in Gualtieri and nearby towns along the river.
“In recent years you could see the bow of the boat, so we knew it was there, but to see the vessel so exposed in March, when it was essentially still winter, was very dramatic,” Bonin said. “I’ve never seen such a drought at this time of year – our main worry used to be our river flooding, now we worry about it disappearing.”
More relics, including a German tank found close to Mantova and the remains of an ancient hamlet in Piedmont, have also re-emerged amid what Italy’s river observatory said last week was the worst drought to affect Po valley in 70 years.
The drought is caused by higher-than-usual temperatures, scant rainfall and much less snow during the winter, particularly in the southern Alps, which in turn contributed to lower snowmelt flowing into the Po.
The situation is so acute that leaders of Lombardy, Piedmont, Veneto and Emilia-Romagna said on Thursday they would ask for a state of emergency to be declared in their regions. Some northern towns require water supplies to be delivered by trucks, and calls have been made for 125 towns to ration supplies of drinking water to restore reservoir levels.
The river’s depth currently measures up to 2.7 metres below the zero gauge, well below the average for June, while its flow rate into the sea has slowed to 300 cubic meters a second – a fifth of the average for this time of year.
The Po valley experienced droughts in 2007, 2012 and 2017, and scientists say their growing prevalence is a further indication of the climate crisis.
“This drought is unique in history due to the combination of two anomalies – the lack of rain, on top of the elevated temperature, which is directly linked to climate change,” said Luca Mercalli, the president of the Italian Meteorological Society.
Mercalli, who lives in a mountain town in Piedmont, added: “It’s as if it’s the end of July in the Alps, water is running out as little snow remains and in a week’s time there will be no more reserves. We recently measured the snow level at a 3,000-metre altitude – usually in June there are two metres but this year not only is there no snow but flowers are already blooming.
“The situation is only going to get worse as the next few months are forecast to be hot and dry.”
The Po valley is a crucial economic area for Italy, enabling industrial hubs such as Turin, Milan and Brescia, along with a vast variety of sectors, to thrive, and is one of the most important agricultural zones in Europe.
Gualtieri is a pertinent example of how small communities flanking the river depend on it. The nature reserve where the submerged cargo ship, which was built in Venice and used to transport grain between the Atlantic and Cremona in Lombardy, came to light was the same area where Italian soldiers who had survived German concentration camps created jobs in timber upon their return home, hence it later became known as Isola Degli Internati (Island for Prisoners).
“Our veterans needed work and this area was rich in willow trees,” said Renzo Bergamini, the mayor of Gualtieri. “They were used to build infrastructure to protect the river’s embankment.”
Bergamini was born in Gualtieri and said climatic events over the past decade had become more abrupt.
“If before we used to get consistent rainfall over 10 months, in more recent years it has come in two or three heavy bursts over a shorter period of time, turning the river into a torrent,” he said.
“Today we’re worrying about the lack of water, which doesn’t only serve farmers for irrigation but energy production and human nutrition – in this area we extract drinking water from aquifers in the Alps but in some areas it is also extracted from the Po and purified.”
In Boretto, further along the Po, a man who usually swims across the river every day was able to walk to the middle of it last week.
“He is known as the god of the Po,” said Jennifer Bacchi, the president of River Passion, a company that organises boat tours and fishing trips, as she navigated along the Po.
“You used to see a lot more ships in this stretch, either for the transport of goods or passengers. Now as you can see, it’s just us, we’re in a motorway of water that is completely empty.”
She said there had been a high rate of holiday cancellations among anglers due to the low water level. “It’s worrying, Boretto really depends on fishing tourism.”
Luca Crose, a manager for commercial shipping at the Boretto unit of Aipo, an agency that provides engineering and environmental services for the Po, including taking daily measurements, said navigation of cargo vessels in the area had to be suspended because of the drought. “The water is not deep enough.”