Why are droughts more severe in Catalonia?

the Water reserves in the inland basins of Catalonia It was found in Historical lowsis the watershed with A smaller proportion of Spain's water reserves. exceptional case Due to lack of rain. The reasons: three consecutive years with half or less of normal precipitation, snow reserves the last three winters below normal, some very unique characteristics of the basin that collects rainwater and water consumption that has stressed this rare and numerous region. Resources needed.

Some empty swamps

We broaden our horizons and look beyond Catalonia to see the specificities of the inland basins within the country's framework. The following map shows the water reserves of the different hydrographic basins in Spain.

sWater reserves in Catalonia's inland basins are the lowest in Spainas a percentage, with one 15,36%. Very close it is Guadalete-Barbate ConcaWhich increased slightly with the rainfall last weekend, from 14 to 15.51%. A severe drought in the Cádiz region has forced authorities to impose severe restrictions on per capita water consumption. The situation is not so critical in the rest of the Mediterranean region, since thanks to the rains that fell during 2021 and 2022, there will be two fewer years of drought. On the other hand, the hydrographic basins of the rest of the northern half of the peninsula have reserves of more than 60%.

Why have we come this far in the interior basins of Catalonia?

There are three criteria that determine the amount of water available in indoor ponds:

Lack of rain. Whether in the percentage of water lost or in liters per square meter that did not fall. In some areas of Catalonia, especially around Montseny, there has been more than 1,000 mm less rainfall in the past three years.

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Conference characteristicsa. If we remove from Catalonia's inland basins part of the Camp de Tarragona and Penedes and the Fluvia, Moga and Tordera basins, what little remains corresponds to the Ter and Llobregat, the basins that supply water to the Barcelona metropolitan area.

High urban demand. 70% of consumption in the inland basins is urban and the remaining 30% is agricultural. This urban consumption corresponds to 117 municipalities with a total population of 5 million people.

It is the combination of these three aspects that makes the delicate situation of the Catalan inland basins so distinctive compared to those of the rest of Spain.

Catalonia has experienced more than three years of scant rainfall

Lack of rainfall is not limited to Catalonia, but we also find deficits in recent years in other regions of the Mediterranean basin. But the difference in intensity that day Duration from until a Catalonia.

We show you a map of rainfall anomalies in Spain for the last four years, from 2020 to 2023, according to Emmett data.

While in 2023 the lack of precipitation was very noticeable throughout the Mediterranean, if we look at 2021 and 2022, we note that incoming precipitation has exceeded that expected in the east of the peninsula, with the exception of Catalonia and the Mediterranean region. Andalusia, which also has three dry or very dry years.

The last rainy year in the Mediterranean was 2020with precipitation mainly concentrated in Chapter one This is thanks in part to heavy rains brought by Storm Gloria in January. The last major disturbance in Catalonia came with Storm Filomena, which left a fair amount of snow but did not affect the annual precipitation balance for 2021.

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Severe drought that lasted more than 36 months

Drought is assessed based on the Standardized Precipitation Index (SPR), which shows the severity of the situation taking into account rainfall. The more negative the value, the greater the dehydration. The following map, produced by Aemet, shows the drought situation over the past 36 months, i.e. an analysis of the rainfall in the past three years.

Since drought does not last a day or months, but years, the ideal solution is to observe it over a long time scale, in this case the past three years. Showing the Iberian Peninsula Two large areas with negative values: One embraces from the Cantabrian mountain range to Catalonia, and the other includes a large part of Andalusia and the provinces of Conca and Ciudad Real. We note that in both drought-affected regions, the most negative values ​​were, Under IPE-3Compatible with Barcelona and Girona provincesthe area in which matches Exactly with part cThe interior basins of Catalonia in the Ter-Llobregat system.

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