Portugal Enters Summer with Reservoirs Near Record Levels — 51 of 59 Dams Above 80 Per Cent Capacity
At the end of March 2026, 51 of the 59 reservoirs tracked by SNIRH were above 80 per cent of total capacity, with Alqueva at 97.9 per cent. After seven storms in 25 days, Portugal enters summer with a water cushion most of Southern Europe would envy — but one heatwave can still draw it down fast.
After one of the wettest storm seasons in recent memory, Portugal is entering the dry months of 2026 with a water cushion most of Southern Europe would envy. According to the Sistema Nacional de Informação de Recursos Hídricos (SNIRH), the monitoring platform run by the Agência Portuguesa do Ambiente (APA), 51 of the 59 reservoirs tracked across the mainland were above 80 per cent of their total storage capacity at the end of March 2026. None were below 40 per cent — a threshold that in past drought years has triggered formal water restrictions across the Alentejo and Algarve.
The Storm Dividend
The favourable position is largely a byproduct of the punishing winter Portugal has just endured. Seven storms hit the country in 25 days, contributing to the EUR 5.3 thousand million damage bill that Lisbon has formally submitted to the EU Solidarity Fund. For water managers, however, that same weather pattern has been close to ideal. Reservoirs in all but one of the country's major river basins are now above the historical average for March over the 1991-to-2025 reference period. Only the Ave basin, in northern Minho, is showing slightly below-average values — a quirk attributed to localised drainage patterns rather than systemic shortage.
The flagship Alqueva reservoir, Europe's largest artificial lake and the cornerstone of southern Portugal's irrigation network, is sitting at 97.9 per cent of capacity — roughly four centimetres from its maximum storage level. Aguieira, in Mortágua, reached 86.5 per cent. The Vouga and Tagus basins are both at or near 97 per cent, with several individual dams in the Tagus system completely full.
What It Means for the Summer
Full reservoirs matter on at least three fronts. The first is agriculture: the Empresa de Desenvolvimento e Infraestruturas do Alqueva (EDIA) supplies water to roughly 130,000 hectares of irrigated Alentejo farmland, much of it now planted with high-value crops including olives, almonds and soft fruit. A full Alqueva means farmers can plan a normal irrigation campaign without the emergency allocations that disrupted the 2022 and 2023 seasons.
The second is electricity. Hydropower accounted for roughly a quarter of Portugal's power generation in years of abundant rainfall — a figure that collapsed during the 2022 drought. With reservoirs full, hydro operators including EDP are expected to run the summer with significantly more generating headroom, reducing Portugal's reliance on imported gas just as the Hormuz crisis continues to push LNG prices up. That dovetails with the government's four-thousand-million-euro grid-reinforcement plan unveiled earlier this week.
The third is tourism. Golf courses, resort pools and urban gardens in the Algarve alone consumed an estimated 60 million cubic metres of water last summer. With regional reservoirs well above the 40 per cent trigger level, municipal restrictions on non-essential use are unlikely to reappear before August.
The Caveat
Water abundance in April, however, does not insulate Portugal from the longer-term trend. Independent modelling published by IWA Publishing in 2025 found that daily soil-water deficits in southern Portugal are projected to deepen through the 2030s even in scenarios of adequate winter rainfall, because evapotranspiration rises faster than precipitation recovers. A full reservoir in April 2026 can be drawn down rapidly by a heatwave in July — as the Algarve discovered in 2023, when 80-plus per cent storage in March gave way to emergency restrictions by late summer.
For now, though, the arithmetic is unusually simple. Portugal has water. The question is whether the country can hold on to it.
