The collective «Bassines Non Merci», which brings together environmental associations, trade unions and anti-capitalist groups opposed to this «grabbing of water» intended for «agro-industry», announced the presence of 10,000 people.

A camp has been set up since Tuesday in a camp set up on the field lent by a peasant, near the site.

The prefect of Deux-Sèvres Emmanuelle Dubée spoke on Friday of around «5,000» demonstrators expected from 10:00 a.m. in this village of around 350 inhabitants, which has become the new epicenter of a conflict over the use of this resource which decreasing with global warming.

At the start of the week, she banned «any demonstration and crowd» around Sainte-Soline to «limit» possible «acts of violence», she justified on Friday, confirming the deployment of 1,500 gendarmes.

Damage and clashes between gendarmes and demonstrators had marred a previous rally in March.

The decree concerns nine other municipalities as well as those of Mauzé-sur-le Mignon, where a first reserve has already been built, and Val-du-Mignon. A driving and parking ban for people coming from outside was added on Wednesday.

Opponents of water reserves, who have planned events on site all weekend, have brought an interim order against these decrees, rejected on Friday by the administrative court of Poitiers.

The participants incur a fine of 135 euros, the court recalled.

– 260 Olympic swimming pools –

About 200 elected officials, lawyers or professors denounced a breach of «the fundamental freedom to demonstrate» in a column published by Liberation. Among the signatories, elected rebellious or environmentalists like Mathilde Panot, Clémentine Autain, Alexis Corbière or Yannick Jadot, announced on the scene on Saturday.

The Sainte-Soline reserve is the second of 16 replacement reserves, at the heart of a project drawn up by a group of 400 farmers united in the Coop de l’eau, to «reduce water withdrawals by 70%», in this region which still experiences irrigation restrictions after an extraordinary summer drought.

These open-air craters, covered with a plastic sheet, are filled by pumping water from surface groundwater in winter and can store up to 650,000 m3 (i.e. 260 Olympic swimming pools). This water is used for irrigation in the summer, when rainfall is less.

Opponents denounce «megabasins» reserved for large export-oriented cereal farms and defend the implementation of other measures to better share and preserve water – agroecology, change of crops, return of grasslands…

The Minister for the Ecological Transition, Christophe Béchu, estimated on Saturday on France Inter that the opponents «denounce something fair, the need that we collectively reduce, and the farmers too, our uses of water», but underlined that A study published in July had «come to say to what extent the project had no negative consequences for the water tables».

According to this study by the Bureau of Geological and Mining Research (BRGM), the project could, compared to the period 2000-2011, increase «by 5% to 6%» the flow of rivers in summer, against a decrease 1% in winter.

Mr. Béchu also recalled that the «plan signed by everyone four years ago» after long consultation between farmers, elected officials, authorities and associations, made access to water conditional on changes in practices (reduction of pesticides, planting of hedges, conversion to agro-ecology).

But out of ten farmers using the first reservoir, «none has subscribed to a reduction in pesticides», according to Vincent Bretagnolle, agro-ecology specialist at the CNRS in Chizé (Deux-Sèvres) and member of the scientific and technical monitoring committee ( CST) of the project, and since the signing, several associations have withdrawn from the protocol.

The organizers of the rally have settled since Tuesday in a camp set up on the field loaned by a peasant, near the site.