Reservoirs in the river basins of Tajo and Guadiana stand at 54.2 and 72.1 per cent of total capacity respectively, according to the Spanish Ministry for the Ecological Transition and the Demographic Challenge’s official weekly figures (MITECO) as at 6 October 2026 . The Tajo basin holds 5,988 cubic hectometres of water, while the Guadiana basin holds 6,875 cubic hectometres. The figures are from the weekly Boletín Hidrológico, which brings together readings from the relevant Confederaciones Hidrográficas .
The current situation is relevant to water management in several regions of Spain. The Guadiana basin, which includes large parts of Extremadura , currently has a much higher proportion of reserves than the Tajo basin, which extends across parts of Castilla-La Mancha and Extremadura. This provides better short-term conditions for agricultural irrigation in the Guadiana area. However, water authorities’ plans in both basins remain dependent on rainfall in the coming months and seasonal demand.
The Boletín Hidrológico provides weekly comparative figures and marks the data as provisional. It is used to inform operational decisions in water management, for example when coordinating water abstraction rules or prioritising between agricultural irrigation, drinking water supply and industrial use. Conclusions about trends and forecasts are limited when based on individual weekly readings; medium-term assessments depend on weather conditions in autumn and winter, as well as regional storage and inflow patterns in the Tajo and Guadiana.
Differences between the basins reflect structural factors: storage capacity and evaporation losses vary, as do the scale of irrigated areas with mandatory outflows and urban demand. Against this background, the Confederaciones Hidrográficas adjust their assessments and, where appropriate, the stages of their drought and water stress plans. According to MITECO, the storage levels published now are the authoritative reference for the reporting period ending on 6 October 2026.
The latest percentages and volumes form part of nationwide reporting on reservoir levels. They provide guidance for local authorities, utility providers, farmers and industry, but do not replace detailed information from regional water authorities. Further updates will follow in the next Boletín Hidrológico, which will track developments in the Tajo and Guadiana.
Editor: Daniel Mayer (Article created with AI assistance).