Reality seems bent on destroying the proverb. At least as far as climatic aphorisms are concerned. In the middle of April —the month of thousand waters, you know— the Ebro Hydrographic Confederation (CHE) has been forced to launch a measure that a priori would seem more typical of August or September than of mid-spring: it has just declare that the Segre basin is facing an “exceptional situation” due to the “extreme drought”. Not only that. Those responsible are already pulling pedagogy and slide that the summer is expected to be “complicated”.
That is the situation in the northeast of the peninsula, but… And the rest of the national canvas?
What happened? That the Ebro Hydrographic Confederation (CHE) has declared the Catalan Segre system in an “exceptional situation due to extraordinary drought”, a tool that offers “greater legal coverage” if you need to apply restrictions. The decision was made at the end of April with a balance of rainfall “much more pessimistic” than expected and a shortage that has led the rivers to a situation more typical of summer than spring.
At the beginning of the week, the reservoir of dammed water in the Ebro Basin stood at 4,287 cubic hectometres, which represents 54% of its total capacity. On the same dates last year, the reserve rose to 5,776 hm3, 73% of its capacity. The difference is therefore 19% in just one year. The gap is even more pronounced if the average for the last five years is analyzed, from 2018 to 2022, which leaves a value of 6,082 hm3, 76% of the total capacity. The data for the reservoirs on the right bank are also lower than those of 2022.
And what is the horizon? Equally or even more revealing are the messages in the code of the future that CHE is launching. Its managers do not rule out adopting measures shortly in other sub-basins, such as the Axis of the Ebro and Lower Ebro, those of Aragón and Arba or that of Iregua, in La Rioja. Heraldo de Aragón slips that the president of the CHE has recognized that before the summer all the systems in the basin could face an exceptional situation. A “complicated” summer is on the horizon, with possible “progressive and more intense” measures.
What does the data say? They don’t leave much room for interpretation. The hydrological year is being sparing in rains and that is felt in a good part of the network of reservoirs in the country. According to Aemet calculations, between October 1, 2022 and April 25, the national average value of accumulated rainfall is estimated at 344 mm. The normal thing for that period would be to reach 455, 24% more.
“The accumulated amounts are below their normal values in most of the Peninsula and archipelagos with many areas that do not reach 75% above their normal value, especially in the eastern and southern half,” he says. The drawing has nuances, of course: the situation is not homogeneous on the peninsula, with areas in which rainfall has exceeded the values of 1991-2020.
And how are the reservoirs? To the half. More or less. The latest hydrological bulletin shows that the peninsular water reserve accumulates 28,074 hm3, which represents 50.07% of its capacity. The data is somewhat better than that registered just a year ago (49.6%), but if we broaden the focus to capture the decade, it is verified that it is a low result: the average of the last ten years is 67.95%, which translated in net terms is equivalent to 10,000 more hm3. The trend is not good: in the last week the peninsular water reserve fell by 0.58%.
If you go down in more detail, it can be seen that the reservoirs for consultative use, those intended mainly for supply and irrigation, are at 41.9%, below the 46.9% that they marked a year ago and far from 64.3. % of the average of the decade. Hydroelectric plants are at 68.3%, above last year, but also far from the average values of the decade.
What is the situation by basins? The latest balance published by the Ministry of Ecological Transition allows us to go down even more in detail. One of his most interesting tables is in fact the one that shows the “portrait” of the country’s reservoirs dedicated to supply. The balance is just that, a “still photo”, but it gives us a valuable idea of what the situation is like in the regions of the peninsula and draw a comparison with respect to 2022 or the average of the decade.
In the internal basins of Catalonia, the percentage of reservoirs dammed as of April 25 was 25.7%. A year ago it was 58.6% and the average for five years and the decade rose to 80.9%. The situation is also delicate in the Guadalquivir or Guadalete-Barbate, both below 30% and which, on average, have moved above 60% over the last decade. Different is the stamp left by the Eastern and Western Cantabrian, Miño-Sil, Galicia Coast and the internal basins of the Basque Country, which although they present lower than usual occupations, they exceed 80%.
Is CHES the only one concerned? No. The drought has led other organizations and companies to pronounce on the situation, which has even gained a relevant place in the political debate. Diario de Sevilla recently published that Aljarafesa acknowledges that if there are no rains in the coming months, it will enter an emergency situation between July and September. “And that entails more rigorous and drastic measures,” notes his manager, who speaks of possible cuts. In March, the Catalan Water Agency (ACA) also pointed out that the Barcelona region “could go into an emergency situation in four or five months”.
Images: Avi Theret (Unsplash)
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