These are not your average reservoirs.
The plastic-lined cavities span, on average, 20 acres—more than 15 American football fields. Nicknamed “mega-basins,” they resemble enormous swimming pools scooped into farmland; about 100 basin projects are in the works across France. In wetter winter months, the basins are pumped full of groundwater; during punishing droughts and heat waves, those waters are meant to provide “life insurance” for farmers, who are among the region’s heaviest water users.