Brittany drought: fear that taps could run dry

All four Breton départements – Côtes-d'Armor, Finistère, Ille-et-Vilaine and Morbihan – remain on 'crise' (crisis) status, the most severe of France's four drought alert levels. No other region in the country is currently in the same position where all departments are affected.

Rivers and groundwater have fallen to their lowest levels ever recorded for the time of year, and reservoirs are shrinking week by week. Water authorities say that unless households and businesses cut back further, some areas could lose their drinking water supply in the coming weeks.

The showers of early September, and the rain that has fallen in recent days, have done little to help. Forecasters expect further rainfall, but say it will be too patchy to reverse the trend, reports franceinfo.

Why is Brittany so vulnerable?

The region's geology is a large part of the problem. Around 75% of Brittany's drinking water comes from surface sources – rivers and reservoirs held back by dams – with only 25% drawn from underground aquifers.

In most other French regions the balance is the other way round. Groundwater reserves respond slowly to dry spells, whereas rivers and lakes drop quickly when the rain stops, leaving Brittany far more exposed to a prolonged drought.

Côtes-d'Armor: 'critical' situation

In a statement issued on October 16, the Côtes-d'Armor prefecture described the situation as critical, saying it was becoming hard to meet residents' demand for drinking water.

The department relies on four dams for its supply. Without significant rain, the prefecture estimates that their reserves will reach a critical threshold within three to nine weeks – a level it says must be avoided, as it is essential to keeping the network running.

The Kerné-Uhel dam at Trémargat, the department's third-largest reservoir, which serves an area stretching from Callac to Loudéac, has fallen by 3.4 metres, from 220.05m to 216.63m. Yann Cauet, director of the Côtes-d'Armor drinking water authority (Sdaep 22), said this was the lowest level measured since the dam was built.

If no rain falls, the reservoir could stop supplying drinking water within around 50 days, even with links to neighbouring networks.

A committee will now meet weekly to monitor reserves and decide on any further measures.

Morbihan: treatment plants shut down

In Morbihan, the river Scorff has almost dried up and the Blavet is also running very low. 

Lorient's Petit Paradis water treatment plant, which normally supplies around 95,000 people in western Lorient, Larmor-Plage and at times Ploemeur, has been out of action since July 22.

A second plant, at Leslé in Pont-Scorff, is running at reduced capacity. It serves Guidel, Quéven, Pont-Scorff, Cléguer, Gestel and Calan, and is only keeping going thanks to water brought in from outside the area and cooperation between local authorities, reports Ouest-France.

On October 13, Lorient Agglomération warned that the flow of the Scorff had dropped below the legal minimum required to produce drinking water. To keep the Leslé plant open, residents are being asked to save 1,000m³ of water a day between them.

The authority has already reduced water pressure in 15 areas, including Gestel, Guidel, Quéven, Cléguer and Pont-Scorff, while taking care to maintain supply to homes and enough water for firefighting. If the savings target is not met, temporary supply cuts may be needed, and several scenarios are being studied. Meanwhile, the Coët er Ver plant in Hennebont is running at full capacity to send extra water to the worst-affected areas.

Further east, the Ar C'Hastell plant at Sainte-Anne-d'Auray, which serves the 24 communes of Auray Quiberon Terre Atlantique, has been put on standby. The Tréauray dam that feeds it is operating at just 20% of capacity.

Françoise Jehanno, director general of services at Eau du Morbihan, which covers almost all of the département outside the Lorient and Vannes areas, said supply was holding up for now, but that the situation remained fragile.

Ille-et-Vilaine: reserves 'until Christmas Eve'

The Ille-et-Vilaine prefecture says the north of the département is in a particularly critical state. The local water producer, Eaux du Pays de Saint-Malo, has called on everyone to play their part in saving water.

Around Vitré, the three dams supplying the area have dropped to 37% of their maximum capacity, down from 70% in August. 

Teddy Régnier, president of the Eau des Portes de Bretagne water authority, said that if there is no rain at all, these reserves should last until December 24. He described the area as being in a state of crisis.

The prefecture renewed its appeal for restraint on the eve of the opening of the Route du Rhum race village in Saint-Malo, stressing that every litre saved now will help protect supplies over the coming weeks and months.

Finistère: emergency reserves tapped

In Finistère, the Saint-Michel reservoir (also known as Lac de Brennilis) has fallen to just 12% of its capacity, forcing the department to take emergency action.

Since October 12, the reservoir's operator has opened the dam's bottom valve, drawing on water from the very bottom of the lake. This back-up reserve is normally left untouched, but is now being used to keep the river Aulne flowing so that drinking water can still be supplied.

Jean-Marc Goarnisson, head of the département's drinking water and sanitation service, warned that without this intervention the reservoir would be empty by November.

If it does not rain before the end of October, the authorities could trigger the Orsec plan in November. Orsec is France's emergency response framework, under which the prefect takes charge of coordinating the response to a major crisis.

What restrictions are in place?

Prefectures across Brittany are keeping in place the restrictions introduced over the summer, which vary slightly from one department to another. They include limits on watering gardens, bans on washing cars at home, and restrictions on farm irrigation and on water use by businesses.

In Côtes-d'Armor, it is currently forbidden to:

• water gardens

• fill swimming pools, whether public or private

• wash vehicles at home

The prefecture has also indicated that exemptions currently granted to professional car washes and to companies cleaning building façades could be withdrawn.

Residents are being urged to go further in their daily habits, for example by:

• taking short showers with a low flow

• only running the washing machine when it is full

• reusing water from washing fruit and vegetables to water plants

Those in Brittany should check the latest rules with their local prefecture or mairie, as measures can change at short notice. Breaching drought restrictions can lead to a fine.

'Everyone will have to be more sparing'

Even when the rain does return, the problem will not be solved overnight. Thierry Burlot, president of the Loire-Bretagne basin committee, warned that a great deal of rain will be needed before the ground is wet enough for water to soak through and replenish rivers and aquifers.

He said consumption on public water networks had risen by more than 5% because of this year's heatwaves, and that everyone will need to use water more carefully.