An episode of rain until Friday generates the expectation of gaining reserves in the face of drought

The arrival of two disturbances in a row this week in northern Catalonia will leave rainfall at the headwaters of the Ter and Llobregat rivers, where the essential reservoirs for supplying the Barcelona and Girona region are located.

Oliver Thansan
Oliver Thansan
22 May 2023 Monday 14:46
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An episode of rain until Friday generates the expectation of gaining reserves in the face of drought

The arrival of two disturbances in a row this week in northern Catalonia will leave rainfall at the headwaters of the Ter and Llobregat rivers, where the essential reservoirs for supplying the Barcelona and Girona region are located. It is not expected that these rains will be much less the solution to solve the drought; but they will be received as water in May.

The long-awaited rains in May are "the last hope" for significant rainfall in the spring, before entering the summer months, a much drier period. May is one of the rainy months in Catalonia.

The forecast of unsettled weather through Friday will increase the chances of four straight days of rain. However, these will not be continuous, but in the form of storms or showers, with maximum records that are very geographically located.

All this occurs when the level of the reservoirs is still at 25%; with 6.3 million Catalans in an exceptional situation and restrictions on agricultural uses, industry and municipal cleaning and irrigation, planned to delay the impact on essential basic domestic services. In recent days, only the Sau reservoir has gained resources. The rains in May have served to stop the decline in reserves.

"We need it to rain for three weeks in a row, constantly, permanently and not torrentially; at least to recover a certain normality", say technicians from the Catalan Water Agency (ACA).

“We have already had two or three episodes of rain. They are certainly very insufficient to overcome the drought, since not much water falls. But evidently all the water that falls in the headwaters of the rivers is usable. It is raining where it touches, especially in the internal basins”, points out Santi Segalà, head of prediction of the Servei Meteorològic de Catalunya (SMC).

The episode of rains last week was very beneficial, since 70 l/m2 were measured in an ideal place, Ulldeter, at the head of the river. It is a good omen. But if the rain falls relatively far from where it is needed, it may not be as helpful.

The SMC expects new rainfall for today that will be concentrated in the eastern half of Catalonia (regions of Girona, north of Barcelona and in central coastal and pre-coastal points). They will not be very important precipitations, but will take the form of a downpour or shower, especially in the afternoon (with amounts that could reach 10 l/m2, or more locally).

Thursday and Friday a second episode of mini-precipitations is expected that will once again affect the northern third and eastern half of Catalonia: the Pyrenees, the Pre-Pyrenees, the Girona and Barcelona regions.

"In this second episode, the amounts of precipitation can be more important and adding the two days can register 30 or 40 liters per square meter", in the areas where there is more rain, according to Santi Segalà. "Where we believe that it will rain little or not at all is in the Pla de Lleida and Tarragona regions," he adds.

In the medium term, between Saturday and Monday little or no rainfall is expected, but new disturbances could arrive from Tuesday.

The decrease in water reserves in rivers has forced a change in all water production schemes. Resources from desalination and the reuse of reclaimed water from Llobregat now provide 58% of the water, while conventional traditional sources (rivers and wells) only represent 42%, according to data from the 23 municipalities served by the company Aigues of Barcelona.