Alqueva: the day the Guadiana was stopped, 8 February 2002

On 8 February 2002 the Guadiana stopped running free through the Alentejo. At a ceremony at the new dam near the village of Alqueva, the gates were closed and the water began to back up behind a concrete arch 96 metres high. The man who gave the order was António Guterres, a prime minister on his way out of office.2 sources2 sources

Not everyone came to celebrate. Environmental activists protested at the ceremony. They said the lake, about 80 kilometres long, would destroy the habitats of eagles and kites and some of the last Iberian lynxes. Engineers expected it to take about four years to fill.1 source1 source

Upstream, in the parish of Luz in the municipality of Mourão, the news landed differently. For decades the dam had come and gone, and the villagers had half decided it would never be built. Only when the gates shut, with their new village already nearly finished, did most of them accept that they would have to leave.1 source1 source

The Alentejo, the great southern plain, covers about a third of mainland Portugal but holds only 5% of its people. Its income per head is below the national average, and it gets too little rain. For generations its farming was rain-fed, what the Portuguese call sequeiro, and lack of water held back both farms and town supplies.2 sources2 sources

The obvious source of water was the Guadiana, the river that comes in from Spain across the eastern Alentejo. In 1957 the Estado Novo, Salazar's authoritarian regime, drew up a Plano de Rega do Alentejo, an irrigation plan for the region, which assumed a large dam at Alqueva.3 sources3 sources

For part of its course the Guadiana forms the border, and the tail of a reservoir at Alqueva would reach into that stretch and even into Spain. A Luso-Spanish convention of 1968 on the use of international rivers gave Portugal the hydraulic use of the border stretch, between the mouths of the Caia and the Cuncos.3 sources3 sources

The project outlived the regime that drew it. In 1975, a year after the Carnation Revolution of 25 April 1974, the Council of Ministers approved the building of the dam. Preliminary works began in 1976: a cofferdam, a tunnel to divert the river and support works for the site. In 1978 they stopped.3 sources3 sources

For more than fifteen years the project went through cycles of advance and retreat, and the people of Luz, under threat of a move since the start, learned to doubt it.2 sources2 sources

An integrated environmental impact study was carried out in 1994 and 1995, and in 1995 the state set up EDIA, the Empresa de Desenvolvimento e Infra-estruturas do Alqueva, a company with public capital, to run the whole project, from the dam to the new village. Excavation restarted the same year.2 sources2 sources

In 1996 the government declared that it would go ahead “unequivocally”, with or without European money, and awarded the main contract for the dam and its power station. In 1997 the project was written into the Community Support Framework for 1994 to 1999, the plan through which EU structural funds reached Portugal. Concrete began to be poured in 1998, and the contract to build the new Aldeia da Luz was awarded in 1999.2 sources2 sources

When full, the reservoir stretches 83 kilometres up the Guadiana valley across the municipalities of Moura, Portel, Mourão, Reguengos de Monsaraz and Alandroal. EDIA and RTP call it the largest artificial lake in Europe; Euronews says Western Europe. It holds nearly four times as much as Castelo do Bode on the Zêzere, now the second-largest reservoir in Portugal.5 sources5 sources

Sceptics had long said there was not enough water in the Guadiana to fill such a lake. The four-year forecast of 2002 proved optimistic, but the reservoir did fill: it first reached its full level of 152 metres on 12 January 2010, almost eight years after the gates closed. By February 2022 it had been full four times and had made three controlled releases.4 sources4 sources

Downstream, the smaller Pedrógão dam forms a counter-reservoir, which lets Alqueva's power station run in reverse and pump water back up. The power stations at Alqueva and Pedrógão began work in 2004 and 2006 and were let in concession to the electricity company EDP. EDIA says Alqueva produces more than 4% of Portugal's hydroelectric power.4 sources4 sources

Luz was a quiet village at the end of a road. The only thing beyond it was the Castelo da Lousa, a Roman building of recognised archaeological value. The village had a fifteenth-century parish church, a cemetery, a bullring and a sanctuary to Nossa Senhora da Luz, Our Lady of Light, who in the legend of its founding had appeared there. All of it lay below 152 metres.2 sources2 sources

How many people lived there depends on who counted. The anthropologist Clara Saraiva, who worked with the villagers through the move, gives about 300 inhabitants and 180 houses. The researcher André Pereira writes of about 200 people, and the news agency Lusa, marking Alqueva's twentieth anniversary, gave about 400.3 sources3 sources

The villagers refused cash compensation. They wanted to stay together, and their demand, in Saraiva's account, was simple:1 source1 source

Building a new village was the answer, about 2 kilometres from the old one, with a street plan copied from it. That was not inevitable: another option was to ring old Luz with dikes. At Portugal's best-known drowned village, Vilarinho da Furna, flooded under the dictatorship in 1972, the people had simply been paid for their land and houses and had scattered.2 sources2 sources

The planning was painful. Families argued over the size of each room in their new houses, and old neighbours grew jealous of each other. EDIA, which was building both the dam and the village, became the enemy.1 source1 source

The people of Luz decided they would not abandon their “alminhas”, the souls of their dead, and that the dead must move before the living. In July 2002, over 13 days, the cemetery was emptied and every grave moved to the new village. The last festa of Nossa Senhora da Luz in the old village was held as usual on the first weekend of September.1 source1 source

Through September and October 2002 the families moved house. The prime minister, by then José Manuel Durão Barroso, inaugurated the new Aldeia da Luz on 19 November 2002, with most of its people already living there. That autumn and winter were wet. In early 2003 the rising water drove the last holdouts from the old village, and in February the old church and bullring were knocked down.2 sources2 sources

The old village was demolished on purpose, so that no ruins would show when the water dropped. Tiles, beams and slate benches were first stripped out to be returned or reused, and the work took from February to September 2003. A museum, which the villagers had asked for since a survey in the 1980s, opened in November 2003 on the first anniversary of the new Luz, between the rebuilt church and the transplanted cemetery.2 sources2 sources

The new houses did not mend everything. A survey four years after the move, by the sociologist João Pedro Reino and colleagues, found the residents on average disappointed with the new village and the community “fragmented”, despite efforts to keep up an appearance of cohesion.1 source1 source

The valley had to be cleared before it was flooded. On 12 February 2001 workers began felling about 1.3 million trees, according to a report at the time. The Liga para a Proteção da Natureza, one of Portugal's largest environmental groups, called it “one of the biggest acts of environmental destruction ever in Portugal” and said a forestry plan and a plan to evacuate wildlife had been ignored.1 source1 source

Quercus, another national group, attacked the economics. It argued that the price charged for the water would not match its real value, against European water rules, and that farming, a declining sector in the Alentejo, offered no long-term answer. The government promised 20,000 jobs, partly from golf courses for tourists.1 source1 source

Then came the rock art. In November 2000 the Spanish authorities reported engravings at the tail of the reservoir, and by July 2001 they had recorded 434 panels, most with Neolithic and later human figures and abstract signs. In April 2001 more were found on the Portuguese side, where a team of 20 combed 75 kilometres of the banks of the Guadiana and its tributaries that summer and recorded 200 panels. An internet petition demanded that they be saved.1 source1 source

In the 1990s Portugal had abandoned a dam on the Côa to save Palaeolithic engravings, and the archaeologist who had led that fight, João Zilhão, now ran the state's archaeology institute. This time he backed the dam. More than a hundred archaeologists had already tested or excavated 222 sites in the valley, and he argued the rock art was neither unique nor in great danger.1 source1 source

Environmental groups proposed a compromise: fill the reservoir only to 139 metres instead of 152. The government kept the full height. In 2002 the protesters at the dam were still warning about the lynx and the birds of prey.3 sources3 sources

The first irrigation block, in the Odivelas scheme, began working in 2002. From the main reservoir, a chain of dams, reservoirs and irrigation blocks carries water across an area of about 10,000 square kilometres in the districts of Beja, Évora, Portalegre and Setúbal. EDIA counts 72 dams and reservoirs in the system.4 sources4 sources

Most farmers took the water. EDIA put take-up of the irrigation at more than 97% in 2021, when 2,675 clients irrigated 117,595 hectares inside and outside the scheme. Over the years they moved from annual crops such as maize, cereals and vegetables to permanent ones, above all olive groves, which EDIA says pay better in the long run and suffer less from swings in price.2 sources2 sources

Spanish investors came first, bringing intensive, mechanised olive groves planted in dense hedgerows. Portuguese growers learned the system, and by 2025 they held 64% of the investment in olives against 31% for Spanish companies. Almonds followed, fastest from 2018.2 sources2 sources

For Portugal the result is measurable. EDIA says the new groves made the country self-sufficient in olive oil after decades of deficit, and its president says Alqueva now produces the largest share of Portugal's olive oil and more almonds than any other part of the country. The olive growers' association Olivum says olive oil exports have grown twelvefold in volume since 2002 and are worth about €900 million a year.3 sources3 sources

EDIA calls Alqueva the largest investment ever made in the Alentejo: €2,427 million by the end of 2021, by its president's count. Since 2010 it has been linked to the reservoirs that supply drinking water to 13 municipalities, Beja and Évora among them, with more than 200,000 people, and in a drought it can top them up. RTP reported that in towns such as Serpa, where water once came at set hours, it is now something people can count on.3 sources3 sources

The argument about who benefits has not gone away. Euronews reported in 2025 that, by EDIA's figures, more than 80% of the water goes to intensive olive and almond plantations, and that a few large companies control most of the irrigated land. Teresa Pinto Correia, a professor at the University of Évora, says the price of water should cover the cost of the infrastructure, and Pedro Horta of the environmental group Zero calls the change to the countryside “an ecocide”. EDIA's president, José Pedro Salema, told Euronews that the dam secures the region's water supply and has brought jobs and investment.2 sources2 sources

Climate change raises a newer question. A study by the consultancy Agrogés expects the water needs of irrigated olive groves to rise by 5% to 21%, while average inflows to the reservoir fall by 5% to 10% by 2050. “We won't have enough water,” Pinto Correia warns. EDIA's president told RTP that the water stored can be managed over several years, and the company is still extending the irrigated area, by about 470 square kilometres according to Euronews.3 sources3 sources