How As Pontes turned a former coal mine into an artificial lake

The former lignite operation in Galicia scarred the landscape for decades. A carefully planned recovery process turned an enormous abandoned pit into a magnificent artificial lake, demonstrating that modern engineering can restore degraded industrial ecosystems while maintaining complete balance.

How did a vast coal mine become the As Pontes lake?

For almost forty uninterrupted years of intensive mining, the open-cast operation removed tonnes of lignite. When work in the area permanently ceased, it left behind a monumental crater 300 metres deep, requiring immediate, structured land rehabilitation measures.

The company responsible for the site drew up a detailed plan to flood the enormous geological void safely. From the first year of trials, technical teams channelled water sources to create a stable reservoir, preventing erosion and ensuring excellent water quality.

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What volume of water was needed to fill the former pit?

Gradually filling the basin required around 547 billion litres of water. The controlled supply used the natural flow of the Eume river, alongside plentiful local rainfall, speeding up the process without affecting the water supply of the neighbouring community.

To prevent the water becoming acidic because of residual coal minerals, specialists treated the banks with lime-based chemical applications. In April 2012, the project reached its intended maximum level, establishing a healthy ecosystem and creating an exceptional lakeside landscape.

Below is a video from the Endesa Channel on YouTube detailing this entire historic process:

What ecological benefits followed the creation of the artificial lake?

The formation of the 865-hectare lake completely reshaped biodiversity across the Galician territory. Various natural habitats began to emerge around the water, including grassland and scrubland areas that attracted wild fauna to the reforested region.

The mine’s former spoil heap underwent extensive reforestation using thousands of carefully selected native trees. This ongoing work created protected wetlands and dense woodland, providing favourable conditions for native animals to establish themselves and for lasting botanical conservation.

Pillars of Environmental Recovery

Core Elements of the Transformation

The main factors that ensured the ecosystem’s restoration at As Pontes were:

1. Chemical neutralisation of the soil and continuous monitoring of water acidity;
2. Reforestation of slopes and spoil heaps with diverse native vegetation;
3. Integration of local catchments to provide continuous natural water renewal.

How do local people use the new leisure space?

The former industrial site has been transformed into an appealing hub for community life and outdoor recreation. The creation of a white-sand beach made water sports possible, boosting family tourism and creating new opportunities for economic development.

The lake’s outstanding water standards earned the inland bathing area Blue Flag environmental certification. Visitors of all ages use its tree-lined paths for cycling and walking, turning the former extraction complex into a safe setting for collective leisure and health.

A variety of public and sporting activities bring the reservoir shoreline to life throughout the year:

• Water sports, including canoeing, sailing and swimming in clean water;
• Paved ecological routes for cycling and walking;
• An artificial beach equipped with shaded areas for family recreation.

What does the As Pontes project teach us about the future of mine closure?

The As Pontes case has become a global benchmark for ecological transition and mine-closure plans. Strategic planning, carried out from the outset of excavation, showed that heavy industrial operations can create a positive legacy for contemporary nature and society.

The successful conversion of the pit highlights the power of technical innovation when it is combined with ecological respect. The Galician reservoir is an inspiring model for governments and companies worldwide seeking to align mine decommissioning with broad sustainability and community vitality.