El embalse de El Atazar alcanza máximo histórico de agua en Madrid

Since this Monday, the El Atazar reservoir has been releasing water through its upper spillway after reaching its maximum storage level: 425 cubic hectometers. This is the third time this has happened since its inauguration in 1972 and has not occurred since May 1991. The first time was in July 1988. «It is an exceptional, beautiful sight that will only be visible for a few days,» emphasized the President of the Community of Madrid, Isabel Díaz Ayuso.

For this reason, the meeting of the Government Council, chaired by the regional president, Isabel Díaz Ayuso, was held extraordinarily at the facilities of this public infrastructure, where they witnessed in situ this water discharge that is expected to continue for several more days.

El Atazar is the largest of the reservoirs in the Community of Madrid and provides 46% of the water supply to the residents of Madrid. Since March, Canal technicians have been carrying out controlled discharges, although not continuous, through its intermediate spillway. Currently, through its three openings (spaces that allow water to pass through), it is releasing a flow of approximately 3 cubic meters per second into the course of the Lozoya River.

At the same time, the regional government plans, for this legislature, the renovation of the entire water supply network in the municipality of El Atazar through the Red Plan, managed by Canal de Isabel II, with an investment of 740,000 euros. This project will cover a three-kilometer stretch.

Current level of the 13 Canal de Isabel II reservoirs

-Pinilla: 91.8% and 34.9 hm3

-Riosequillo: 96% and 48 hm3

-Puentes Viejas: 84.1% and 44.5 hm3

-El Villar: 101.6% and 22.8 hm3

-El Atazar: 100.3% and 426.3 hm3

-El Vado: 92.5% and 51.5 hm3

-Pedrezuela: 93.6% and 38.3 hm3

-Navacerrada: 85.9% and 9.5 hm3

-Santillana: 97% and 88.5 hm3

-Navalmedio: 72.3% and 0.5 hm3

-La Jarosa: 87.4% and 6.3 hm3

-Valmayor: 98.4% and 122.4 hm3

-La Aceña: 100.3% and 23.8 hm3

More than 112 liters per square meter in April

The report on the hydrological situation of the 13 Canal de Isabel II reservoirs also reveals historical data on water contributions received during the past month of April. Thus, a quantity of 112.3 liters per square meter was obtained, 84% higher than the historical average for the same period. Likewise, for this May, it is expected to reach 78 liters per square meter, 29% higher than the average.

The forecast for the first eight months of the hydrological year, which began in October 2024, is 769 liters per square meter, 48% higher than the historical average (520.8 l/m2). With these reserves, the water supply is guaranteed for a long season, but despite this, the public company insists on the need for responsible water use and conservation of this resource.

Actions to ensure hydrological security

Additionally, Canal de Isabel II has carried out nearly 250 actions in the dams so far this year to ensure their safety, regulate river flow, and mitigate the effects of floods. Decisions on these maneuvers, including opening or closing gates or varying released flows, are made by analyzing flow measurements, weather forecasts, statistical series, and the operational models of each dam.

On the other hand, the heavy rainfall has also had consequences on wastewater treatment. In March, the treatment plants processed 61.49 million cubic meters, the highest amount in a month in Canal’s history. In April 2025, they treated 54.24 hm3, making it the third month in history with the highest amount of water treated.