France would need it to rain for several weeks if not months to collect enough water to put an end to the historic drought conditions currently affecting the country, experts have said.
Rain returned to some parts of France last week but forecasters at Météo France have said that it will take more than the usual summer showers to have any impact on the drought.
The water table is still very low, due to a relatively dry winter and the summer heatwaves. Levels are especially low in areas such as Provence, the Côte d'Azur, and Poitou.
Today (August 17), there are eight French departments under an orange storm and flood warning as heavy rain is expected.
All metropolitan French departments are currently under drought warnings or alerts, with most seeing the highest level of restrictions imposed. Less than a centimetre of rain fell in metropolitan France in July.
Laurent Lucaud, vice president of Grand Poitiers in charge of water and health, told FranceInfo: “Some of our spring flows are less than half [the typical amount] this season.”
He said that on Sunday and Monday (August 15), it rained just 15 millimetres in the area, which he called “just a little storm”.
He said: “We would need relatively abundant rain for several weeks, maybe even several months, to make up for the water deficit.”
He added that the water deficit in the area was now at “hundreds of thousands, perhaps even millions, of metres cubed”.
Summer rain does not normally contribute much to water table levels. Heavier rainfall in autumn and winter typically helps, although the water table is the last to recover after rain. It only begins to refill once the ground is already fairly saturated.
Water expert Vazken Andreassian said: “Rain helps the soil and the plants. The soil is the first to benefit and allows plant life to restart. On the other hand, the water tables have to wait: they are the last to be served.
“Recent rain will solve the problem of surface rivers, but the water table levels are still waiting.”
And yet, too much rain in one go can cause a risk of flooding, as drought-stricken ground struggles to absorb that much liquid.
Mr Andreassian explained: “Very intense rainfall does not benefit the soil or the water table, because there is a runoff phenomenon, which can create floods.”
However, Mr Lucaud in Poitiers, said he fears for water supply if there is not sufficient rain, which can be absorbed, in the next few weeks and months.
He said: “Our reserves are dropping each day. If we add a lack of water supply to this existing crisis, the deficit will increase. We are already on the reserve of the reserve. Disruptions in the supply of drinking water over a period from November to December are unheard of.”
The situation is not as bad everywhere. In the north, the Paris area and the Pyrenees, water table levels are normal, around average.