Britain. Water in reserve despite the light rains

From May to September, Brittany was little watered. Nevertheless, groundwater levels are generally close to average. Only the Côtes-d'Armor are "vigilant".

While 62 départements, affected by the drought, are affected by restrictive measures, Brittany is rather spared. Of the four departments, only the Côtes-d'Armor are, since 21 September, in a state of "vigilance" . A prefectural decree "encourages" individuals and professionals to save water. Globally, from May to September, "the rains were below normal" , observes the BRGM (Bureau of geological and mining research), in charge of watching over the underground water reserves.

As a result, "the tablecloths of Brittany present mainly a declining level," note the hydrogeologists in a bulletin of October 5. While summer rains are usually absorbed by vegetation or evaporated by heat, September rains can begin to recharge the aquifers. With few exceptions, this has not been the case this year. "Globally, we have not started to have a start of soil recharge , " says Chantal Gascuel, director of research at INRA (National Institute of Agricultural Research).

Scenario less bad than in 2017

However, says Rennes hydrologist, "the state of the tablecloths is average. 2018 is not a particularly dry year . And the rainy autumn and winter of last year had raised the levels of the underground reserves. "This year's scenario is less bad than 2017," says the researcher. The observation of the soil moisture level has not justified, at this stage, any particular monitoring being triggered.

The BRGM, however, observed lower than normal water table levels in the western part of Finistère, "linked to a rainfall deficit in recent months" . But the measurements also show above-normal water table levels, "mainly in Ille-et-Vilaine".

The weather in recent months, considered "not exceptional" , "does not allow, in terms of climate, to release a trend," says Chantal Gascuel. Nevertheless, she says, "what has been observed over the past 10 years is greater variability, with very dry years a little more frequent".