Adaja river · Duero Basin · dam built in 1995 · latest official reading: 6 October 2026.
Las Cogotas is currently at 37.9 % of capacity, about normal for the time of year. The week-41 average across 27 years of records is 37.6 %, a difference of +0.3 points.
For context: a year ago it stood at 50.0 % and a month ago at 43.1 %. Against last week’s reading it is essentially flat (+0.0 points).
Blue line: average monthly filling across the whole record, from 1999. The dot marks today’s reading, 37.9 % in October.
With 1,441 weekly readings since 1999, the average pattern of Las Cogotas is clear: it peaks in June at 79.2 % and bottoms out in November at 35.1 %. That 44-point range makes it a reservoir with a marked annual swing, typical of heavy irrigation use.
The highest reading in the whole series is 107.3 %, on 20 May 2003, and the lowest 6.8 %, on 13 November 2007. 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 58 hm³ of capacity it is the 19th largest of the 35 dams the bulletin tracks in the Duero basin, holding 0.8 % of the whole demarcation’s capacity on its own. The basin as a whole is at 48.9 % today, so this reservoir is running below the basin as a whole.
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 1999. 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.
