“We will have to learn not to store water on the surface, if it has to evaporate or if we cannot fill the reservoirs”, alert this Sunday on franceinfo Bernard Barraqué, emeritus research director at the CNRS and specialist in water management in Europe and France, while France is experiencing a historic drought. Instead, Bernard Barraqué recommends “to collect rainwater and store it in places where it quickly seeps into the ground, because it does not evaporate”.
franceinfo: Are we really water wasters in Europe?
Bernard Barraque: Everyone wastes, we could save a lot of water everywhere, and we will have to learn how to do it. We will also have to learn not to store water on the surface, if it has to evaporate or if we cannot fill the reservoirs, as is already the case in Spain. The country is indeed in a process of aridification, whereas it had built more than a thousand small water reservoirs during the Franco period. But today, because these reservoirs are in single file on the rivers, they can no longer fill them when it does not rain upstream. In France, we also risk being affected, so we should perhaps not engage, as some of the agricultural profession does, in the act of retaining water.
Why are you against these water reservoirs?
As scientists, we are neither for nor against water retention. We fully understand the problems of farmers faced with drought, and it is really dramatic for them. But we have changed our regime: we are in the phase of climate change which means that it is no longer worth making water reservoirs, if we do not fill them. On the other hand, what countries that have experienced droughts before us are already doing is storing water in the soil. Where possible, it is essential to collect rainwater, when there is any, and store it in places where it quickly infiltrates the soil. Because it does not evaporate and can be spread further.
Can wastewater be a solution to waste less water?
Italy and Spain reuse 10% of their wastewater. France, according to the latest figures, would be at 1% because of excessive caution from the health authorities. Much more needs to be done, especially for agriculture. We are in a situation where we will have to share water a lot more, and store it in a more sustainable way.