Ecuador’s Mazar reservoir drops 10 meters in 45 days as Colombia restricts hydropower exports ahead of El Niño

The Mazar reservoir water level fell from 2,153.32 meters above sea level on July 26 to 2,143.72 meters on September 9, 2026, according to Corporación Eléctrica del Ecuador records. The decline accelerated in early September, dropping three meters between September 1 and September 9 alone, equivalent to consuming more than 20 million cubic meters of water. The reservoir has now depleted approximately 20 percent of its 300 million cubic meter useful volume, or roughly 60 million cubic meters. The current level remains 31.72 meters above the critical operational threshold of 2,115 meters, at which point power cuts typically begin, but the rate of decline has triggered concern across Ecuador’s energy sector.

The 31-kilometer reservoir feeds the Paute Integral hydroelectric complex, comprising the Mazar plant at 170 megawatts, Paute-Molino at 1,100 megawatts, and Sopladora at 487 megawatts. Together these facilities represent 1,757 megawatts of installed capacity, covering between 38 and 40 percent of Ecuador’s national electricity demand. Any sustained reduction in Mazar’s reserves directly threatens grid stability nationwide.

Three concurrent factors drive the reservoir’s rapid depletion. River inflows averaged just 54.4 cubic meters per second during the first eight days of September, well below the historical average of 75 cubic meters per second and September 2025’s 66.93 cubic meters per second. National electricity consumption reached approximately 4,430 megawatts per hour daily in August, exceeding the National Electricity Operator’s 3,945 megawatt projection by nearly 500 megawatts. This demand spike occurred before the typical peak consumption months of December and January.

Colombian electricity transfers to Ecuador collapsed from an average of 281.1 megawatts daily between September 1 and 6 to just two megawatts on September 9. Colombian President Abelardo de la Espriella announced the “Energy Now Plan” on September 7, prioritizing domestic supply as El Niño intensifies. The new framework permits Colombia to export only after satisfying its own demand, restricting hydroelectric sales and allowing only thermal generation exports priced at the most expensive production cost plus transmission charges.

Ecuador’s dry season began in September 2026, approximately one month earlier than the historical October start, and will persist through March 2027 according to the Ministry of Energy. Technical reports from Cenace estimate Ecuador faces an energy deficit between 1,300 and 1,391 megawatts during severe drought conditions without Colombian imports. The government initially announced plans to add 920 megawatts of new thermal generation in 2026 through 525 megawatts of leased capacity and 395 megawatts of purchased units, but the Vice Ministry of Electricity acknowledged in August that only 50 megawatts of leased generation would come online during the year.