Two prefectural decrees authorizing the creation of fifteen water reservoirs intended for agricultural irrigation in New Aquitaine – nicknamed “megabasins” by their opponents – were canceled on Tuesday October 3 by the administrative court of Poitiers, whose judgment highlights their unsuitability facing the effects of climate change.

These projects, attacked by environmental defense associations, aimed to create and exploit so-called “substitution” reserves with a total capacity of around 3 million cubic meters. Their principle consists of taking water from surface aquifers in winter, to make it available to irrigating farmers in summer when rain is rare.

The first prefectural decree authorized the creation of nine reservoirs planned in the Aume and Couture basins in the departments of Charente, Charente-Maritime and Deux-Sèvres, the second decree provided for six reservoirs in the sub-basin of La Pallu (Vienna).

These megabasins are highly contested in the region, where demonstrations by opponents, banned by the authorities, gave rise to violent clashes with the police around a basin under construction in Sainte-Soline (Deux-Sèvres). ), on March 25.

In a press release, the Vienne prefecture announced that it would appeal this decision. Bertrand Lamarche, president of the La Pallu water management cooperative, told the daily La Nouvelle République that irrigators in the area would “certainly” appeal, too.

“Inaccuracies, omissions and inadequacies”

For Julien Le Guet, spokesperson for the Bassines non merci collective, this court decision is a “great relief” and “very good news for all those who fight for water and against megabasins”. For its part, the Peasant Confederation believes in a press release that “this judgment fully legitimizes the request for a moratorium on megabasins” and that “all projects and all megabasins must cease immediately.”

Local environmental defense associations, allied with the UFC-Que Choisir, the Confédération paysanne dans la Vienne, as well as the League for the Protection of Birds, had seized the administrative court of Poitiers to have the prefectural decrees having authorized, in 2021, these projects carried out by collectives of irrigating farmers.

Concerning the Aume-Couture basin, the decision identifies “inaccuracies, omissions and inadequacies” in the environmental impact study of the nine planned basins. The latter had “the effect of harming the complete information of the population”. The court also considers that “the project is not associated with real water saving measures and does not take into account the foreseeable effects of climate change”.

In Vienne, the judges point to an “oversizing of the project” in terms of the volumes of water to be taken to fill the reserves, with regard to what the local hydrological environment “is capable of providing in satisfactory ecological conditions” and taking into account the “predictable effects of climate change”. The court concludes that there was “a manifest error of assessment” by the prefecture “in the implementation of the principle of balanced and sustainable management of the resource” defined by the environmental code.