Groundwater and the river Loire lack water. The Prefecture has issued notice to limit and even prohibit withdrawals. Loire-Atlantique, Vendée and Maine-et-Loire is in a state of “crisis.”
What is the current situation ?
Loire-Atlantique, Vendée and Maine-et-Loire is in “crisis,” according to the site Propluvia, the Ministry of ecology and solidarity Transition. This is the highest degree of drought alert levels.
“In these three departments, there is almost every year restrictions on the uses and water withdrawals, notices Stephanie Poligot-Pitsch, head of Hydrology Division of the Regional Directorate of the Environment (Dreal). This is normal, but the situation is more critical this year.” More earlier this year, as the peak of drought is often reached in August.
Why have we this drought?
Everything is dependant on the weather between September 2016 and March 2017 at the “charging period”. “At that time, the rivers are full because there is no evaporation phenomenon,” explains Mathieu Dauphin, meteorologist at Meteo France. But this year, rainfall was well below the seasonal average.
In Nantes, it fell 364 ml of water, 559 ml against average. Le Mans experienced its second driest season since 1945, with 233 ml of rain against 425 ml. The Vendée also ran out of water, especially in the plains and in the grove.
“On the scale of the Loire Valley, it fell from 50 to 70% of what it usually falls, summarizes the meteorologist. This is a very important deficit because six-month figures generally tend to even out.” Most ordinary rains in March and May did not reverse the trend. And the heat wave in June amplified the consequences of water shortage on water resources.
What measures were taken?
The prefects of the five departments have issued orders of restriction and / or prohibition of water withdrawals on specific sectors. The measures taken for the moment concern mainly farmers and watering gardens and green spaces. They are not about the drinking water supply network. But the government has made a call for vigilance.
Has the rain of recent days not been enough?
“The rain already has some effects, says Stephanie Poligot-Pitsch. It reduces the water demand of farmers, allowing rivers to find a little more speed, and is good for the fauna and flora.“
Water supply remains superficial. “Raindrops irrigate cm of soil, but it makes no difference to the deeper layers,” said Mathieu Dauphin.
Prospects for the coming weeks?
For this weekend, Meteo France expects the heavy rain in the region, with rainfall in the order of a few tenths of millimeters or even tens of Mayenne. The beginning of next week could be marked by thunderstorms, accompanied by a rise in temperatures is expected to continue from Wednesday.