PARIS (Reuters Life!) - One hundred years ago, the river Seine burst its banks and filled the elegant boulevards of Paris with torrents of muddy water, forcing thousands of inhabitants out of their homes and cutting off power for months.
The same could happen again. Only this time the consequences will be 10 times worse, experts say.
"The flood is unavoidable," said Louis Hubert, director for the Paris region at France's ministry of ecology and sustainable development.
"What we can simply say is that we are almost certain to see new considerable floods, but we don't know when."
Paris' centennial flood of 1910 -- a flood which has a 1 in 100 chance of occurring every year -- affected 200,000 people in 1910 and cost 1.5 billion euros ($2.15 billion) in today's money, said Hubert.
A similar flood these days would affect around a million inhabitants and cost 15 billion euros, he added. On top of this, another two to three million people are likely to see their electricity cut off for several days, he added.
"In both cases, there are 10 times more people concerned, and the direct cost is ten times more that of 1910. It could lead to disorganization of the Paris region and have an effect on the national economy," added Hubert.
To commemorate the 1910 flood, Paris' Galerie des Bibliotheques is exhibiting a collection of photos, postcards and witness accounts.
Among them are sepia shots of bowler-hatted, mustachioed men traveling piggyback, trousers hoisted and knee-deep in water; a totally submerged Champs de Mars; people pulling up to Notre Dame cathedral in boats and food being delivered by ladder to second-floor apartment windows.
In most cases, Parisians seem to take the catastrophe with humor, smiling wryly at the camera while perched on precarious makeshift structures above swirling water.
Since 1910, Paris has taken pains to boost its defenses, by raising the height of bridges, scooping out a deeper riverbed and carrying out hydraulic work.
But nowadays, increased urbanization and the proliferation of electricity and telephone networks mean more people are vulnerable, Hubert added.
Such preparations would help bring down a water level of eight meters (yards) by 60 cm (24 inches) at the most, Hubert said.
"In spite of everything, the flood, if it happens, risks having consequences at least as extensive or even more so."
Paris museums at risk of flooding such as the Louvre, Musee d'Orsay and Musee du Quai Branly will be able to spirit the priceless works stored in their basements to a safehouse at Cergy-Pontoise, a town northwest of the French capital.
"We have a flood plan and are working hard on it. If anything happens we hope to be warned in time by the Paris fire brigade," said a member of the Louvre Museum's communications team, adding that the center should be finished by 2014.
For now, photographs from 1910 are on display in Paris to warn the city's inhabitants of what to expect.
"I am not here to scare people, but the scenario will be catastrophic enough," said Pascale Dugat, member of La Seine en Partage, which is hosting a gallery on www.seineenpartage.fr.
"These are agreeable, convivial photos to say: 'yes, we are threatened; yes, it's going to happen; yes it will be more catastrophic,'" Dugat told Reuters by telephone.
"And then we will take our little pets and seek refuge in the countryside," she said.
Editing by Paul Casciato