8 reservoirs with a combined capacity of 1,651 hm³ · latest official reading: 1 September 2026
The Guadalete-Barbate demarcation is currently at 77.9 % of capacity, far above normal for the time of year. The week-36 average across 38 years of records is 47.0 %, a difference of +30.9 points.
For context: a year ago it stood at 44.5 % and a month ago at 80.7 %. Against last week’s reading it is falling (−0.5 points).
Blue line: average monthly filling for the whole demarcation since 1988. The dot marks today’s reading, 77.9 % in September.
With 2,018 weeks of record since 1988, the average pattern of the Guadalete-Barbate demarcation is clear: it peaks in April at 61.9 % and bottoms out in October at 44.1 %. That 18-point range makes it a moderately seasonal demarcation.
The highest reading in the whole series is 97.8 %, on 9 April 2013, and the lowest 2.0 %, on 7 November 1995. Comparing today against those two extremes says more than the bare percentage: 50 %% is comfortable in a demarcation that rarely tops 60 %%, and worrying in one that usually reaches summer full.
By capacity it is the 8th demarcation of the 14 covered by the hydrological bulletin: its 1,651 hm³ account for 2.9 % of everything Spain can store in mainland reservoirs. Today it holds 1,286 hm³.
The 8 dams the hydrological bulletin tracks in the Guadalete-Barbate demarcation, sorted by capacity. Linked names have their own page with the full record.
| Reservoir | Capacity (hm³) | Volume (hm³) | Fill | Δ week | Use |
|---|---|---|---|---|---|
| Guadalcacín II | 800 | 687 | 85.9 % | −0.2 | Irrigation / supply |
| Barbate | 228 | 165 | 72.4 % | −0.4 | Irrigation / supply |
| Zahara-El Gastor | 223 | 150 | 67.3 % | −0.4 | Irrigation / supply |
| Bornos | 200 | 136 | 68.0 % | −1.0 | Irrigation / supply |
| Hurones, Los | 135 | 96 | 71.1 % | −0.7 | Irrigation / supply |
| Celemín | 45 | 36 | 80.0 % | +0.0 | Irrigation / supply |
| Arcos de la Frontera | 14 | 13 | 92.9 % | −7.1 | Irrigation / supply |
| Almodóvar | 6 | 3 | 50.0 % | −16.7 | Irrigation / supply |
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 1 September 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.
National summary and reservoir search on Reservoirs of Spain.
