What are France’s ‘mega reservoirs’ and why are they so controversial?

After violence erupted at a reservoir protest in western France, we explain why the projects have attracted so much anger

The reservoir water is intended to enable farmers to water crops in the summer months but activists say they are unacceptable during a time of water shortages
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The violence that marred a protest in Sainte-Soline (Nouvelle-Aquitaine), western France at the weekend has put so-called “mega reservoirs” under the spotlight.

Here we look at the arguments for and against them and explore why they are so controversial.

Read more: Man in coma after ‘intolerable violence’ at France reservoir protests

What are the reservoirs?

They are enormous “basins” that store water that farmers can use to water crops and do other agricultural work during the spring and summer months. They look like huge swimming pools but also have pumps and pipes around them.

The basins pump water from the underground water table during the winter (when the water table is supposed to be replenished by rain) to store for drier months.

The intention is that farmers have an uninterrupted source of water and do not need to take groundwater in the summer when there is less rainfall.

How many are there in France?

There is not one single official figure for how many “basins” there are in France. However, one government website suggests that there are around 100 such projects.

The campaigners Bassines non merci and Le Soulèvement de la Terre say that there are in fact around 300.

Where are they in France?

The “basins” are typically constructed in large fields or on farming land.

Most of them are found in the west of the country, mainly in Charente-Maritime, Vendée, and in Deux-Sèvres.

Sainte-Soline, which is in Deux-Sèvres, is (along with another site at Mauzé-sur-le-Mignon) part of a project of 16 reservoirs around the Sèvre and Mignon river basin near Niort.

These 16 reservoirs alone will stock a total of six million cubic metres of water and will be used by a cooperative of 450 farmers, with support from the state.

In the Vendée, there are around 25 reservoirs, which were constructed between 2007-2011. A new project for 30 new reservoirs in the Clain river basin, in Vienne, was approved at the end of 2022.

Vincent Bretagnolle, a researcher at the CNRS, told FranceInfo that there are several reservoirs in this area due to the granite soil. Made up of dense rock, water cannot infiltrate it, which means that any crops grown on the land need more frequent watering. This is especially true for maize crops, which are common in the area.

What are the arguments in favour of the reservoirs?

Farmers have called them their “life insurance policies” in case of dry summers, and say they are essential to protect their ability to grow crops and provide food even when water would otherwise be in short supply.

Former farmer and MEP Jérémy Décerle told TF1: “It allows farmers, in a time of drought, and during the summer when it’s more difficult to grow, to benefit from a bit more water to grow their crops.”

One farmer in Deux-Sèvres told LCI: "It is essential that this succeeds in our area, where half of the irrigated farms will disappear. Without a replacement reserve, we cannot guarantee agricultural production on a national level.”

Why are they controversial?

Critics and campaigners say that they represent unfair “water sharing” practices and a “theft” of water at a time when water is becoming scarce and groundwater levels are historically low.

Opponents also say that the reservoirs waste a huge amount of water due to evaporation – around 20%.

Over the past few months, the water table has not been replenished as usual, with environmental experts warning that this will likely cause a severe lack of water this summer.

Prefectures and local authorities have already begun to impose water restrictions as a result.

Activists say that the reservoirs treat the symptoms of the problem while worsening the cause. They argue that instead of hoarding water, society needs to rethink how we use water in everyday life and for farming.

One protester told TF1: “We’re here to defend water. Everywhere we look, we’re being told that we have to restrict our water use, so we’re here to avoid this monopolisation [of water sources].”

What is the legal status of the reservoirs?

They are all legal, in that their construction has been approved via official channels. However, campaigners have managed to cast doubt on their usefulness and appropriateness during the current water crisis, and the construction of some has been overturned in court.

Several reservoir projects are currently the subject of court cases and campaigns by activists. These include 93 reservoirs being built in the old Poitou-Charentes region.

In January, the administrative court of appeal in Bordeaux cancelled six projects in Charente-Maritime, saying that the amount of water planned for the reservoirs was “excessive”.

Later, in February, the Conseil d’Etat court banned five more reservoirs in the department from being filled due to a lack of studies on their impact.

Read also: Several injured in ‘water basin protest’ in France: what happened?

Are more protests planned?

Yes. Activist campaigners say that up to 10,000 people are set to attend protests this Saturday (April 1), again at Sainte-Soline, which has become a symbol of the wider issue.

Authorities say that around 7,000 people may attend, including 1,000 ‘ultra’ protesters who could turn violent. Last weekend, the gendarmerie used quad bikes and tear gas to dispel the protesters.

Organisers say that there were 30,000 people present, while the gendarmerie put the figure closer to 6,000. Campaigners claim that at least 200 protesters were injured. Of 3,000 law enforcement officers present, 28 were injured and two were hospitalised. Two journalists were also injured.

One protester remains in a coma after being hit by an as-yet-unidentified projectile. Official figures say that seven protesters were taken in by emergency services, and three were severely injured.

Investigations are underway to determine what happened.

Interior Minister Gérald Darmanin condemned the violence, saying that “you can be at the reservoirs without throwing Molotov cocktails”.

But opposition leader Jean-Luc Melenchon has said that “these reservoirs damage water reserves in France”. He blamed the violence on the heavy-handedness of officers, and said that “without the [riot police] BRAV-M, nothing would have happened except for a walk in the fields”.

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