Temperatures and rainfall of the last few days may perhaps make us forget last sweltering summer, but autumn 2022 has been exceptionally dry and the effects of the summer drought will probably be felt throughout 2023
"Rain fall down... but what does it do?". Unfortunately it does not do enough, answering the question of an old Italian song. The rain of the last few weeks may banish the memory of the driest summer in 70 years (we talked about it here), but they do not solve the problem of water resources for Italian peninsula. In fact, even if the topic is no longer in the headlines, the autumn of 2022 has been stingy with rain. Rainfall below the seasonal average and unusually warm temperatures are threatening to lengthen the tail end of the driest summer in decades. Negative rainfall anomalies until October were up to 90% below average, for example in southern Piedmont (TgR Piedmont 2022).
Although it has started to rain again, especially in north-western Italy, this is not enough to overcome the water crisis we are experiencing. When we talk about “drought” we do not only mean the weather and climate condition of absence (or scarcity) of rainfall, but also the consequences on water resources and the ability of supply systems to guarantee the water necessary for daily activities. As a matter of fact, we do not feel the lack of water at the moment because our needs have decreased as the irrigation of the fields has ended. But next spring the problem will arise again with the same urgency, so if there is a lack of adequate rainfall in the coming months, we will experience a water crisis again.
Meteorologists warn that only an exceptionally wet November and December could compensate for the lack of rainfall accumulated over the summer.
Reminding us of this there are the lakes, rivers and aquifers that have not yet fully returned to normal levels. For surface water reserves, such as lakes and rivers, refill times are shorter (a couple of months), instead for underground aquifers it sometimes takes months or even years, explains Emanuele Romano, a researcher at the CNR's Water Research Institute, during an interview with Linkiesta (Beretta 2022).
Although the Po River's water availability (runoff values, reservoir levels in the Great Lakes and salt wedge rise) has partially improved compared to October, the last bulletin of the Permanent Observatory on Water Uses in the Po River Hydrographic District still described the basin's water severity as 'average (with rainfall)' (Po River Basin District Authority 2022). However, the rains of the last few weeks have already allowed a first recovery. In the case of the Po basin, much will also depend on the snowfall in the Alps and on spring temperatures, which should not be too high and in advance of the season. If water is not immediately available, there is no risk of a shortage when it is needed most. The continuity of the rainfall is also crucial and it is important that it is constant, even if not intense, so that the water does not slide over the surface without accumulating.
The climate crisis confronts us with a real risk of long-term drought that we will no longer be able to deal with as a crisis, but which we will have to adapt to and mitigate as a new normality.
Researcher Romano explains to Linkiesta how in the short term it is important to act with three different ways: reducing consumption, reuse treated wastewater in agriculture, and intervene on leaks in the water distribution system. However, structural investments are essential to deal with the climate emergency, environmental challenges and hydrogeological risk. And all this must be among the government's primary goals.
References
Po River Basin District Authority. «OSSERVATORIO PERMANENTE SUGLI UTILIZZI IDRICI NEL DISTRETTO IDROGRAFICO DEL FIUME PO». Monthly bulletin, 2022, bulletin n. 18/2022.
Beretta, Chiara. «Coda lunga, Non se ne parla (quasi) più, ma la siccità continua a mordere».. 29 10 2022. https://www.linkiesta.it/2022/10/coda-lunga-siccita-temperature-anomale-autunno/ (consultato il giorno 11 29, 2022).
TgR Piemonte. Autunno caldo e secco, l'allarme dell'Arpa. 3 11 2022. https://www.rainews.it/tgr/piemonte/articoli/2022/11/autunno-caldo-e-secco-lallarme-dellarpa-561610bc-6ba2-4414-a9e0-ff1af27dfada.html (consultato il giorno 11 30, 2022).