Tormes river · Duero Basin · dam built in 1970 · latest official reading: 6 October 2026.
Almendra is currently at 55.8 % of capacity, about normal for the time of year. The week-41 average across 38 years of records is 62.7 %, a difference of −6.9 points.
For context: a year ago it stood at 73.7 % and a month ago at 66.2 %. Against last week’s reading it is falling fast (−3.9 points).
Blue line: average monthly filling across the whole record, from 1988. The dot marks today’s reading, 55.8 % in October.
With 2,023 weekly readings since 1988, the average pattern of Almendra is clear: it peaks in June at 71.8 % and bottoms out in November at 60.1 %. That 12-point range makes it a very stable reservoir through the year, as hydropower pools and very large dams tend to be.
The highest reading in the whole series is 99.1 %, on 1 June 2010, and the lowest 25.1 %, on 27 September 2022. Comparing today against those two extremes says more than the bare percentage: 50 % is good news in a pool that rarely tops 60 %, and bad news in one that is usually full.
At 2,649 hm³ of capacity it is the largest of the 35 dams the bulletin tracks in the Duero basin, holding 34.8 % of the whole demarcation’s capacity on its own. The basin as a whole is at 48.9 % today, so this reservoir is running above the basin as a whole.
The bulletin classifies it as a hydropower reservoir. That matters when reading the percentage: these pools fill and empty with electricity demand rather than the irrigation calendar, so a sharp drop does not necessarily mean scarcity.
The figures on this page come from the official MITECO reservoir archive, the same database behind Spain’s weekly hydrological bulletin. The bulletin covers every mainland reservoir above 5 hm³ of capacity and is published every Tuesday with Monday’s reading.
The latest reading here is from 6 October 2026, and the comparison series starts in 1988. Nothing is estimated, interpolated or forecast: the percentage is stored volume divided by the usable capacity the bulletin itself assigns to the dam. Historical averages are computed over the same calendar week in every previous year, the only fair comparison in a system with such marked seasonality.
See the whole demarcation, with all 35 dams the bulletin tracks: Duero Basin.
