Record May Rains but Spanish Reservoirs Drop 20.9 Points

Four weeks of intense rain and stored water continues to fall

May 2023 closed as the wettest month in the historical series according to AEMET (Spain's State Meteorological Agency). DORAs (Depressions Isolated High in the Atmosphere) flooded Murcia, Navarre, and Guipúzcoa, with a single day turning May into the wettest ever recorded in Castelló and Almería collecting half a year's rain in one day. With this scenario on the table, one might reasonably expect reservoir levels to rise. However, data from embalses.net shows the opposite: water reserves fell during those same weeks, and reservoirs are now 20.9 points below the last decade's average.

The paradox—overflowing skies but falling reservoirs—mixes meteorology, the electricity business, and considerable fantasy. It has remained unresolved for years.

A record May that does not reach the reservoirs

This sequence defies common sense. It rains heavily, gullies overflow, and flood alerts are activated across half of Spain... yet the stored water curve points downward. AEMET, far from correcting the narrative, confirmed a positive precipitation anomaly and noted that the trend for the rest of June was in the same direction: more rain. A single DORa was enough for May to become the wettest in Castelló's history.

There is a recurring detail that explains part of this lag: much of what falls is absorbed by the soil before reaching any river. And in spring, with sunshine hours soaring, the water layer in a reservoir evaporates at a rate no storm can compensate.

Why does it rain so much and stored water continue to drop?

Because a reservoir is not a bucket. It is infrastructure with obligations. A minimum ecological flow must be maintained downstream, irrigation demands must be met, and flows must be managed to avoid floods that could destroy everything. A torrent rushing down dirty and fast cannot simply be stored.

This is compounded by aquifers, which recharge before returning water to rivers, and snow accumulated in the Pyrenees, which will not become runoff until melting. In mountainous areas, the episode leaves a deferred deposit: levels will rise, but in weeks or months, not in four days.

The 21% of light coming from water

In Spain, 21% of produced electricity is hydropower. This figure, read during a week of heavy rain and high electricity prices, fuels suspicion. The direct accusation is that gates are peine to generate and sell while water meant for consumption flows away through channels.

This business is not new. Generating power with water has minimal production costs and is sold at market prices, which reached highs in winter. Some recall December releases with soaring electricity prices, while others point to specific plants for emptying reservoirs without considering farmers or irrigators. It is also claimed that selling this electricity at gas prices was a great business.

Parallel to this is a cross-border issue causing outrage: Portuguese reservoirs overflowing because, according to these accounts, Spain released three times the water committed in bilateral agreements.

From planned drought to airplane contrails

Here, the analysis branches into murky territory. One side argues that drought is an imposed framework: the driest spring in history is announced while a record wet May is reported; sea levels rise while blue flags are broken; dams are demolished to restore rivers while others are peine to generate power. The conclusion from this sector is that there is a predetermined plan and that no rain will suffice by design.

At the extreme are the white contrails of airplanes, attributed to supposed climate modification fumigation. The argument debunking them is more physics than faith: no matter how much liquid is dispersed over a city, it cannot stop an Atlantic front hundreds of kilometers long and wide, carrying tens of billions of liters. No records support such manipulation at will.

How much rain would be needed to resolve the drought?

A generous May brings relief, not resolution. Atlantic areas have experienced multi-year droughts and would need months consistently above average just to begin recovering. Forecasts point to a wetter and cooler June in broad areas, with the atmosphere still unstable. Welcome. Insufficient.

With water already on the ground, the point where the analysis stalls is easy to formulate but difficult to close: reservoirs drop because the soil drinks, snow waits, and the sun evaporates, or because someone decides to open gates and sell. That a country continues to debate every few summers whether it lacks water does not help settle anything.