the ghost of drought has not yet gone away

Spain’s reservoirs accumulate water. Quite. The balance published on Monday by the Government shows that the water reserve is at 73.4% of its capacity, which is equivalent to about 41,100 cubic hectometers (hm3), almost 3,000 more than last year and 9,300 than the average of the last decade. Now, that does not mean that Spain can breathe free from the specter of water cuts. On the contrary. Reserves have been declining for months while warnings echo of those who remember that droughts must be solved with the swamps still full.

There is a revealing fact: the water reserve has been reducing since may and Galicia activated weeks ago the pre-alert for “moderate shortages” in several areas.

The percentage: 73.4%. That is the level of occupancy of the reservoirs. He last balance from the Ministry for the Ecological Transition and Demographic Challenge (Miteco) shows that the swamps of peninsular Spain, with a capacity of 56,042 hm3, currently store 41,110. If we go down to detail we see that there are areas in which the stock is much higher and others in which it is clearly lower.

In Júcar the reserves are at 60.8% and in Galicia-Costa at 65.2% while in the internal basins of the Basque Country or Catalonia they exceed 85%. In general, the Atlantic side remains at 74.8% and the Mediterranean side is around 68.8%.

Is it a bad balance? No. Not at least if we take into account the panorama that Spain faced in other years at this point in the summer. At the end of July 2025, the country’s dams they remained at 68.4%with just over 38,300 hm3 of water, and there were certain regions in which the outlook was very worrying.

The water reserve stored in the Segura basin It didn’t even reach 29%when now exceeds 56%. In general, Miteco itself recognizes that the dammed water is higher than that of a year ago and the average for the last decade, which is at 31,831 hm3. This is the case in both the Atlantic and the Mediterranean.

It’s not all good news. No. And that’s probably the most important part. Perhaps the current water outlook is not bad, especially if we compare it with that of recent years, but there is one fact that cannot be omitted either: reserves have been declining for months and there is no hope of that changing.

In fact, this negative trend can be traced back to May 19, when Miteco calculated that the reservoirs were above the 84% of its capacity. A month later that indicator had already dropped to 80.1% and on Monday it was at 73.4%.

Dams that empty. A quick Google search comes up to find news about swamps that are slowly emptying. It happens with the Ciudad Real reservoirs and Salamanca or in Andalusia and Estremadurato cite a handful of examples. In Galicia the Xunta even went one step further and opted two weeks ago for activating the “pre-alert for moderate water shortage” in the Lérez and Anllóns and Costa da Coruña river systems up to the border with Arteixo.

In Vigo have activated also the pre-alert. There at the beginning of the month the mayor, Abel Caballero, assured that there was water for five months and that its main dam, Eiras, has fewer reserves than it accumulated around the same time in 2017, the year in which the region suffered one of its worst droughts.

How is that possible? Very easy, due to the peculiar meteorology that Spain is encountering this year. The winter was very rainy. So much so that Miteco calculates that it was the eighth with the most rainfall since it began collecting data on the subject, in 1961. So far in the 21st century there has only been two others in which the most water was collected, 2000-2001 and 2009-2010.

This explains why in March the reservoirs accumulated just over 46,800 hm3 of water for human, agricultural and industrial consumption, 83.5% of its capacity. In the entire historical series there is no March with a better indicator.

From that stage we went to a spring particularly “dry”during which 75% of what has been normal for that season between 1991 and 2020 was collected on the peninsula. In June the change was even more radical. The Aemet calculates that the average precipitation in peninsular Spain was just 12.4 mm“which represents 39% of the normal value for the month,” he clarifies. In the historical archive From the agency there are only two Junes in which the umbrella was less needed.

“It is worth thinking about the drought”. It is not about being catastrophic with the reservoirs at 73.4% of its capacity, but it is advisable to keep in mind reflections such as the one I left in April in The Conversation Jorge Rodríguez-Chueca, professor at the Polytechnic University of Madrid (UPM).

Despite the good water reserve data that Spain had at that time, the expert warned: “It is at this time when it is appropriate to think about the drought.” The reason is very simple: strategies must be drawn up when there is still water in the swamps, not when we have dragged on for months with hardly any rain.

The other figure: 32,000 hm3. Although the copious winter rains had allowed Spain leave behind the state of drought that the country has been dragging since 2021Rodríguez-Chueca insisted: “It is now, when the reservoirs are full, when the drought must be addressed through planning and awareness.”

“The amount of water impounded is only a specific image, not a guarantee for the future,” insisted the UPM expert before slipping in a key piece of information: Spain’s annual consumption is around 32,000 hm3. “Drought does not appear suddenly, it is a cumulative process. If consumption remains high, the system may seem safe. But if it also rains less, it can quickly become vulnerable.”

This reflection was important in spring, with the reservoirs gaining volume, and it is even more so now, in the middle of summer, with water reserves receding.

Images | Juanje Orío (Flickr) and Mytec

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