Ter river · Catalan Inland Basins · dam built in 1962 · latest official reading: 6 October 2026.
Sau is currently at 68.5 % of capacity, above normal for the time of year. The week-41 average across 38 years of records is 53.0 %, a difference of +15.5 points.
For context: a year ago it stood at 61.8 % and a month ago at 73.3 %. Against last week’s reading it is falling fast (−1.8 points).
Blue line: average monthly filling across the whole record, from 1988. The dot marks today’s reading, 68.5 % in October.
With 2,023 weekly readings since 1988, the average pattern of Sau is clear: it peaks in June at 71.5 % and bottoms out in October at 53.2 %. That 18-point range makes it a reservoir with a moderate annual swing.
The highest reading in the whole series is 100.0 %, on 28 January 2020, and the lowest 1.2 %, on 5 March 2024. 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 165 hm³ of capacity it is the second largest of the 7 dams the bulletin tracks in the Catalan inland basins, holding 24.4 % of the whole demarcation’s capacity on its own. The basin as a whole is at 73.0 % today, so this reservoir is running closely in line with 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 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 7 dams the bulletin tracks: Catalan Inland Basins.
