Prague's response to last month's floods is both heartbreaking and heartening, writes John Banville, who has just returned from this most precious, historic city

Legend has it that the name of the Vltava river is made up of two words from the lost language of the Celts, vlt, meaning wild, and va, meaning water. In normal times the visitor to Prague would think this an unlikely derivation. The great, broad river - in places it is a third of a kilometre wide - meanders its way through the city, skirting an island here, there spilling gently over a weir, placid, it would appear, as a village stream. More than one of Prague's disenchanted writers have seen in it a symbol of what they consider the shallowness of the people who live along its banks; as the fantastical novelist Gustav Meyrink sourly observed, a foreign fool might think the Vltava as mighty as the Mississippi, but in fact it is "only four millimetres deep and full of leeches". But T.S. Eliot got it right when, in the Four Quartets, he declared:

. . . I think that the river

Is a strong brown god - sullen, untamed and intractable,

Patient to some degree, at first recognised as a frontier;

Useful, untrustworthy, as a conveyor of commerce;

Then only a problem confronting the builder of bridges.

The problem once solved, the brown god is almost forgotten

By the dwellers in cities - ever, however, implacable,

Keeping his seasons and rages, destroyer, reminder

Of what men choose to forget.

Certainly, a large number of Praguers had forgotten just what the river could do when its back was up. There have been many floods in the city over the past hundred years - in 1890 two arches of the Charles Bridge were washed away - but none so terrible as this summer's cataclysm. On the night of August 8th-9th, after a week of torrential rains, a vast surge of waters gathered in southern Bohemia and began to race toward the capital, swamping and in some cases destroying villages and towns along the way: Ceský Krumlov, Ceský Budejovice, Písek, Strakonice, techovice . . . Prague was unprepared for what was coming.

By the time the waters began to subside on August 14th, an entire district of the city, the former industrial centre and lately yuppified Karlín, had been virtually obliterated, half the Metro stations were closed - and will remain so indefinitely; a charge of criminal negligence has been laid against city officials - precious old buildings had been damaged, some beyond repair, and tourist figures had fallen by 50 per cent. The cost of repairing the waterlogged fabric of the city will run into billions of Czech crowns, and no one knows where the money might be found. It is a European disaster.

Praguers take pride in the fact that their city sits at the geographical centre of Europe, its jewelled heart. The Czech lands, of which it is the capital, have a troubled history - as what country in that troubled continent does not? Czechs today speak of the defeat at the Battle of Bílá Hora, or White Mountain, in 1620 as if it were a contemporary catastrophe. In that battle, the Protestant forces of the young Frederick, the Elector Palatine, appointed King of Bohemia by the Prague Diet, and known afterwards as the Winter King, were crushed by the Habsburg Emperor Frederick II, Jesuit-trained hammer of the Lutherans. The following year, on June 21st, 27 Czech dignitaries, Protestant nobles, knights and city burghers, were publicly executed on the Old Town Square. Following the executions, the heads of 12 of the dead were displayed in iron baskets on the Charles Bridge, their severed right hands, and the tongue of one of them, the Rector of Prague University, Johannes Jessenius, nailed to their skulls. It was, as the scribes have it, a day of infamy in the history of the Czech lands.

An indication of the convolutions of that history is the fact that, in the words of one contemporary chronicler, "there never was an easy 'one-word' way (such as 'Czechia') to describe this part of the world". Over the centuries the borders of what is now the Czech Republic have been as fluid as the Vltava itself.

After the Bohemian collapse at White Mountain, the country became a focus of international squabbling, from the Thirty Years' War right through to 1918, when it was joined to Slovakia and achieved independence at last, an independence that was to last for a mere 20 years, until the betrayal at Munich, to the Czechs another White Mountain. And no sooner had the Germans gone than the Russians arrived . . .

One needs to know something of these successive defeats and invasions to appreciate the full extent of the shock that Praguers felt as they cowered before the raging waters of the Vltava last month. Here was yet another assault on their city to be resisted.

Suddenly, the thing in their midst that they had "almost forgotten" literally rose up against them. People in the city speak of their incredulity and growing horror as day after day they watched the water levels rise; one Irish diplomat based in Malá Strana, the ancient "Little Quarter" on the left bank, told of walking to the embassy each morning and looking down successive side streets and seeing the fringe of dirty water inching its way inexorably upwards. At its highest, the flood rose to a height of some four metres; one can still see the high-water mark on the houses, shops and restaurants of Malá Strana.

Most of the bridges are closed to all modes of conveyance save trams and taxis, the ban enforced by soldiers and armed police. Traffic is even more chaotic than usual; one commuter said that travelling by tram in the city now reminds her of the public transport system in Calcutta: "The trams are so crowded, people are practically sitting on the roofs!"

Prague has always been one of the most mysterious of European capitals. It has a long history of magic and alchemy, in part the legacy of Emperor Rudolf II, that strange, solitary monarch and mad collector of exotica, who at the beginning of the 17th century brought to Prague a mixed rabble of alchemists and necromancers, including John Dee, Elizabeth's court magician and model for Prospero in The Tempest, and his familiar, that most colourful of charlatans, the peg- legged and earless Edward Kelley.

Something of the atmosphere generated by these wonder-workers remains even yet, not only in Golden Lane hard by the Castle on Hradcany hill, where legend says that Rudolf housed his alchemists, but in the Old Town, too, and even in the New. You turn a corner from a crowded boulevard and find yourself suddenly in a cobbled alleyway, silent, deserted, and somehow suggestive of dubious intent. Walk into St Vitus' Cathedral, or the gilt-and-black Tyn Church on the Old Town Square, and something seems to breathe in your face, an exhausted, soundless sigh out of a shadowed past. The floods have intensified this mysteriousness, as if the flood waters, coursing through the catacomb of cellars and underground passageways beneath the city, had stirred something ancient and elemental in Prague's very foundations.

For Praguers, there is no romance in any of this. The city may smell like Venice now, but this rank odour will attract no visitors. Businesses have been ruined; some of the biggest and most expensive hotels are closed, and will remain so, possibly for years; precious murals have been washed off the inner walls of Renaissance buildings in Malá Strana; getting to work is a nightmare. Yet, as everyone in the city, native or foreign, will attest, Praguers showed magnificent spirit and capability in dealing with the crisis.

All the same, the question remains: who will pay? A flood tax proposed by the government was voted down by parliamentarians who suspected a ploy to raise taxes in general. On Wenceslas Square students are selling symbolical bricks to raise funds for flood repair. The gesture is heartbreaking, but also, despite the pathos of it, heartening.

John Banville's latest novel, Shroud, will be reviewed by Bernard O'Donoghue in The Irish Times Weekend supplement tomorrow.