The reservoirs of the Ter and Llobregat rivers, which supply the Barcelona and Girona region, currently accumulate half of the necessary flows to overcome the risks of drought. The reservoirs are at 29% of their maximum capacity on these June dates, so they present the same percentage that they showed at the beginning of February of this year.
It is the evidence of a globally very dry spring despite the recent downpours, very localized geographically.
“What would be expected in a normal spring would have been to have twice the volume of water that we currently have,” says Enrique Velasco, head of the water resources management department of the Agència Catalana de l’Aigua (ACA).
After the latest rains, the Barcelona area has seen the risk of domestic restrictions recede, as explained last week by the president of Agbar, Ángel Simón.
However, this entire central area of ??Catalonia is still in an exceptional situation, which means that there are still limitations for various uses of water (agricultural irrigation, in industries, irrigation of parks and gardens, and urban cleaning). The situation is, therefore, far from being normalized.
The five large reservoirs of these Catalan rivers accumulate 176 cubic hectometres, while to definitively remove the dangers of drought it would be necessary to have 341 cubic hectometres (55% of the total). This is the threshold that marks entry into a pre-alert situation (and which involves the first special measures: increase in desalination water, activation of wells, first controls).
After the rains, the Sau reservoir has recovered (it reaches 24% and had dropped to 7% in April), but the Ter-Llobregat system as a whole continues at very low levels continuously, which proves a persistent drought. In four months the reserves have only been maintained.
If we analyze what normally happens in spring (the time of year when there is a greater contribution of rain), it is verified, for example, that on March 1, 2018, the Ter and Llobregat reservoirs were at 49% (302 hm3) and that in summer (on June 21) reached 95% (581 hm3).
These figures illustrate the seriousness of the situation, considered “critical”. “To have an optimal volume of reserves to face the summer months with guarantees, we should be between 48-50%,” say ACA sources. With this level (some 100 hm3 more than what we currently have) the demands (urban, agricultural irrigation and environmental flow) could be guaranteed.
The months of March and April were very dry and only in the months of May and June have rains begun to occur. But they have not been generalized episodes of several days, extensive and continuous, but punctual and geographically located, although they have the virtue that they have soaked the ground.
In the current phase of exceptionality in which the Barcelona region finds itself, the restrictions are focused on the agricultural, livestock and industrial sectors (with cuts of 40%, 30% and 15%, respectively); and, in addition, the use of drinking water for irrigation of parks and public and private green areas, among others, has been prohibited. In the domestic sphere, the provision of water to the municipalities is 230 litres/inhabitant/day.
In addition, an emergency has been avoided thanks to desalination and reuse, which are now the central pivot of the supply (account for 58%) in the 23 municipalities in the Barcelona area served by Aigües de Barcelona. Desalination accounts for 33% of the demand, while 25% are regenerated flows (the rest is water from the river and wells).
After yesterday’s downpours, scattered showers are expected today, although not as intense. “We forecast extensive but scattered rain. We do not expect it to rain everywhere at once”, says Santi Segalà, head of forecasting at the SMC. Between Thursday and Saturday, three days of truce are expected, without precipitation and with rising temperatures. And between Sunday and Tuesday, a new disturbance will arrive that can cause storms, but not widespread.
