International marine and climatological experts believe that Venice is dangerously unprotected

Decisive days for Venice



Venice is no natural environment. It is the result of man’s continuous modification of his environment over thousands of years; it stems from a dialectical relationship with the surrounding waters. The potential of the waters has been exploited to its fullest extent, but the city itself has also had to be protected from the waters’ ravages by sophisticated engineering works. We need think no further back than the end of the last century, when the great dykes were constructed to protect the three entrances to the harbour that connect the lagoon to the sea.

During the last one hundred years the sporadic high tides (acque alte) that partially immerse the city have grown alarmingly more frequent. According to the Venezia Nuova consortium, charged by the Italian government with the preparation of “studies, plans, experiments and projects designed to restore hydrological equilibrium to the lagoon, and to decrease the level of the tides”, since the beginning of this century recorded instances of tides more than eighty centimetres above the average height have increased from ten in the first half of the twentieth century to more than forty in the second, and have reached sixty in the last five years.

During the past two years (1996 and 1997) the event known locally as acqua alta has exceeded 100 centimetres on thirty-six different occasions. This figure can be understood with reference to Piazza San Marco: when the tide reaches one metre or more above its average height the whole of St Mark’s Square is under water.

In 1966 the tide was nearly two metres above the average height. The weather was unusually violent and in several places the natural barriers between sea and lagoon, from the Lido to Isola di Pellestrina, were breached. The city was truly terrified. Suddenly her vulnerability became clear, as did her defencelessness and lack of preparedness. Twenty-three hours of deepest anxiety ensued. It was then that the threat posed by violent storms and dramatic weather conditions began to be appreciated. Active measures were taken; work began on the strengthening of the defences against the sea.

It was at that time that serious thought began to be given to ways of defending the city from the tides even when they were not unusually high. The Venice lagoon has a surface area of 550 square kilometres and is in contact with the sea at three different points—at S Nicolò, the Lido and Chioggia. The problem was to regulate the amount of sea water coming into the lagoon. Permanent barrages were obviously out of the question. The rise and fall of the tide keeps the lagoon alive, bringing in fresh water as it rises and removing polluted water as it falls. More than one solution to the problem was found.

First, the inhabited parts of the lagoon that were most liable to flooding were given special protection.

Second, it was planned to instal a system of mobile barriers at the points where the sea enters the lagoon. The first plan for these barriers was drawn up in 1981 and, after years of study and improvement, was finished in 1992.

Three years later, in 1995, the Comune di Venezia submitted the plan for mobile barrages at the three harbour entrances to evaluation by the Environmental Impact Procedure (VIA). The government commission has been reinforced by a body of five international experts, appointed by the Italian government. Their report was delivered on 8 July 1998. The experts have given the go ahead to the mobile barriers, with due caution, and have authorised them as environmentally sound as well as adequate to the function they are designed to carry out.

It would be reasonable to hope that, in the wake of such a positive report, the project would be speeded up and that words would soon be translated into deeds. There was time when discussions about the future of Venice were referred to as a “lagoon of idle chatter”. Nothing has changed. Nothing has happened. The Committee of the Ministry of the Environment, headed by the Green Party minister Ronchi, will now give its opinion of the report by early October. The Ministry’s experts, thought by some to be a great deal less qualified than the international group of experts, will decide whether to accept or reject the work carried out by the respected group of experts appointed by their own government. Hitherto the Green’s view has been that there must be no mechanistic intervention in the Lagoon, rather, a host of ecologically “friendly” interventions.

Some have proposed raising the floor level of 40% of the city, beginning with the insulae, so that buildings would be protected from tides up to 120 centimetres high. But this would take sixty years to achieve and by the time work was finished, sea level would already have risen. The mobile barrages would take eight years to construct, although a similar project in Amsterdam was carried out in two.

Some specialists point out that the plan to elevate parts of the city and to create enormous drainage and insulation tanks underneath various buildings and groups of buildings has been gone into less carefully than has the plan for the mobile gates. In addition, old buildings are subject to a continuous process of movement and settlement. To make their bases rigid, it is suggested, might subject them to the same problems as in the basilica at Assisi, where the disastrous effects of the 1997 earthquake were accentuated by recent repairs that had made the structure too rigid.

What are political reactions to the mobile barriers? The majority of members of the Ulivo [the party in government, a centre-left coalition] are sceptical, if not openly hostile, apart from the few who welcome everything that the Minister of Public Works, Paolo Costa, suggests. The left-wing Venice city council is opposed to the barriers, but this may be less through honest conviction than because of the fear that adoption of the plan might cause a split with the Greens, which would spell the downfall of the present coalition. In the opinion of others it is fear that an investment of almost L4,440 billion (£1.5 billion; $2.4 billion) would deprive the city of funds that could otherwise be used to restore buildings for many other purposes.

There are also worries about the life of the port. If the level of the sea rises by ten centimetres the mobile gates, between October and April (extra high tides are extremely rare during the other months of the year) would have to be closed every six days. While the situation remains as it is, closures of three to seven hours are expected every ten days, on the same months. One of the experts has said: “This would mean that the port would have to increase in efficiency and services in order to attract business. They would have to make a virtue out of a necessity.”

What is the city’s reaction to all of this? Vittorio Pierobon, a keen observer of Venetian affairs and chief diarist of the Gazzettino observes that, “For the time being the city is fairly indifferent. When things intensify, protests will begin. There is a risk that the most determined and vociferous of the minority parties, the Green Party, will have its way”.

Originally appeared in The Art Newspaper as 'Decisive days for Venice'