Venice’s Santa Lucia railway station is packed as visitors scuttle across the concourse towards the water-bus stops. Taking a selfie against the backdrop of the Grand Canal, Ciro Esposito and his girlfriend have just arrived and are unimpressed with what may greet them in future if the Venetian authorities get their way: a minimum city entry fee of €2.50 throughout the year, rising to between €5 and €10 during peak periods.

It is the price of a cappuccino, but for them “it’s going too far”. “They are using people like a bank machine,” says Esposito. “We are in Europe and can travel freely across borders, yet we have to pay to enter one of our own cities.”

In earlier times it was the wheeled suitcases that tourists rattled over the cobbles that drew the ire of Venetians – so much so that the authorities pledged to fine anyone caught using one up to €500. That never happened, but now another – more plausible – penalty is being concocted. To manage the impact of the 30 million people who visit the lagoon city every year, the daytrippers – those who come, take pictures, and leave – are to be forced to pay, although it is unclear when the tax will be introduced or how it could be enforced.

Venice may have a centuries-long history of cultivating tourism, devising crowd-drawing events such as the annual carnival, the Biennale international art exhibition and a star-studded film festival, but the advent of mass tourism has left it struggling with how to deal with the near-constant hordes who trudge around its precious sites, through its 11th century basilica, over its famous Rialto bridge, and along its maze of winding calle. The influx is a blessing for the local council’s coffers but a scourge on the city’s fragile monuments and environment.

Luigi Brugnaro, the Venice mayor who regularly lashes out at uncouth tourists, is increasingly under pressure to act. Not only does he face local elections next year but, in July, Unesco will decide whether or not to put the fragile city – battered by increasingly frequent flooding and swamped in summer by tourists – alongside America’s Everglades National Park and the rainforests of Madagascar on its list of the world’s endangered heritage sites.

For many Italians, though, the charge is not the answer. Even those who welcome it are sceptical that it will make a real difference. The entrance fee will not apply to those who have booked hotel rooms, and visitors already pay a tourist tax of up to €6 per night if they stay in the city.

Dealing with flood water has become a way of life in Venice. Photograph: Stefano Mazzola/Awakening/Getty Images

“If people want to come, then they will still pay to come,” says Clelia Tanzarelli, a regular visitor from Rome. “Venice is a very delicate city and there needs to be some plan, but if this is just an extra tax then it won’t solve the problem. A better solution would be to limit visitor numbers.”

As with the wheeled suitcases, the dilemma is how on earth to turn the plan into a workable and enforceable policy. There have been suggestions that the charge could be added to the cost of arriving in the city either by train, bus or cruise ship, with the respective transport companies passing the proceeds on to Venice authorities.

While it is not possible to drive in Venice, people can arrive in the mainland area of the lagoon and park their vehicle for between €12 and €29 a day. Charging cruise-ship passengers is fairly straightforward – they could pay on the boat or as they disembark – but applying it to other modes of transport and distinguishing between Venice residents and visitors will be more challenging.

“Beyond the announcement, it doesn’t seem to have been well thought out,” said Dominic Standish, a British academic and author of the book Venice in Environmental Peril? Myth and Reality.

“But the paradox of this measure is that the authorities bemoan tourism and say Venice is becoming like Disneyland, but if they’re able to implement it, then it will make the city even more like Disneyland.”

The notion of the fee appealing to residents may also backfire. Venetians have held several protests in recent years against a tourism industry which they argue has eroded their quality of life, damaged the environment and driven residents away. On some days the current population of 55,000 (down from about 175,000 in the post-second-world-war years) is dwarfed by the number of tourists.

Brugnaro has said that some of the extra cash from the fee will help fund the cleaning up of rubbish that daytrippers leave in their wake and improve the lives of locals, but many of those same locals are enraged by the idea that the charge would also have to be paid by departed Venetians visiting home and family. Understandably, that is not something they can celebrate.

“It’s like adding insult to injury,” said Marco Gasparinetti, who leads the Gruppo 25 Aprile activist group. “After forcing thousands of people to leave the city, you now force them to pay to visit their families? The tax would make sense if it was a way to offset the environmental impact of the cruise ships, as other than for cruise passengers, it’s very difficult to apply.”

Attempts to divert massive cruise ships away from St Mark’s Square will take years to complete. Photograph: Andrea Merola/EPA

In a move to allay environmental concerns, Brugnaro tried to indicate to Unesco in late 2017 that he was getting tough on the cruise ships that, weighing more than 96,000 tonnes, disembark thousands of passengers in the heart of the city. They would no longer be able to sail past St Mark’s Square, he announced, and would instead take a less glamorous route via the industrial area of Marghera.

Environmentalists have claimed that waves caused by the cruise ships have eroded the underwater supports of historic buildings and polluted the waters. But the plan is yet to be approved by the national government. If and when that approval comes, work on the new route, which requires the dredging of canals and construction of a new port, would take an estimated four years. And while diverting the ships would better preserve the historic centre, the move will do little to address concerns about pollution.

It goes without saying, however, that Venice’s troubles are not limited to tourism. The city is also endangered by recurring acque alte, or high waters. On 29 October last year, three-quarters of the city was hit by the worst flooding in a decade. Rain poured for almost 24 hours, with strong winds raising the water to 156cm above the normal sea level – a record reached only five times in the history of the city. As tourists persevered with their holidays – wading through knee-deep water in wellies and venturing to deluged shops and restaurants – locals counted the cost of the damage.

And the reckoning continues. A local newspaper has referred to the autumn flood as a day that Venetians will never forget.

For the second time since 2000, water filled St Mark’s Basilica, causing damage to the marble floors, bronze metal doors and mosaic floors of the 1,000-year-old church. A few days after, the cathedral’s administrators made the striking claim that the damage had caused the structure to age “20 years in one day”. Initial repairs are costing about €2.2m but Marco Piana, one of the administrators, said the major concern was the long-term impact of the damage.

Tourists throng the Rialto bridge in summer. Photograph: Marco Brivio/Getty Images

Administrators said the damage would have been avoided if the multibillion-pound Mose project designed to prevent flooding in the Venice lagoon had been up and running. Work on the flood barrier began in 2003 but has been dogged by delays and myriad issues, including a corruption scandal that emerged in 2014 and saw former mayor Giorgio Orsoni accused of accepting bribes in return for awarding contracts.

The latest estimated completion date is 2022, and the administrators have urged the national government to finish it as soon as possible.

“Around 96% is done, so there is just a small bit left to do, but they keep pushing the date back … all of this depends on the funding coming from the government,” said Piana.

The floor of the nearby Caffè Florian, one of Italy’s oldest and most famous coffee houses, was also damaged by the floods, as were several shops.

Most locals grin and bear the high water when it occurs. “It does bother us when it happens but we’re used to it, and the tourists have fun with it,” said Michele Levorato, who runs a stall next to the Rialto bridge. He added that most locals also learned to live alongside the tourists, although he would like to see a “better quality” of visitor. “Many don’t respect the city,” he said.

In advance of the Unesco deadline, authorities have tried other initiatives to better manage tourism, such as installing turnstiles at the two entry points to the lagoon during peak periods in an attempt to control the crowds heading towards St Mark’s Square and the Rialto. They are also trying to encourage people to visit other, lesser-known areas of the Venetian lagoon or one of its other islands, such as Murano and Burano.

But the uniqueness of Venice will forever hold an allure, making it unlikely that the measures will have much impact.

“If they want to improve the city they need to invest in better infrastructure in order to move people around better,” said Standish. “An underground train system is something that has been debated for decades but the current administration is unwilling to consider it. This is partly the issue – they don’t seem willing to make things better. They just have this anti-tourism bias.”