Dams in the North are up to 90 percent full, but dams in the Algarve are still seriously short of water.

It seems entirely logical to link the dams north of the Algarve with local dams. Not surprisingly, it’s not that simple. Most, if not all, of the Algarve dams, are connected, you can see the green pipes and ventilation units sometimes if you are observant. They are very obvious along the Silves to Algoz road, you can also see the pipes crossing above the old road to Lisbon as you approach Albufeira.

The environmentalists, and let’s face it we blame them for everything, say that removing water from regional dams will damage the local ecosystem. The benefits and challenges of connecting dams in Portugal revolve around striking a balance between meeting energy and water demands and protecting the environment. Interconnected dams can provide water supply, flood protection, and hydropower generation benefits. Nonetheless, these benefits must be weighed against the potential negative effects on local ecosystems and natural flow patterns.

Meeting water needs

Portugal's dam network and water management system play a crucial role in meeting the country's water and energy needs. Dams store water primarily for human consumption, irrigation, and energy production, with some interconnected to ensure consistent water supply for power plants even during droughts. For instance, Iberdrola, a Spanish energy giant, built two dams on the Tâmega River, about six miles apart, as part of a giant pumped storage hydroelectric project in Portugal.

With extensive talk about drought in Portugal, (despite the recent rain), it’s important to understand where our drinking water originates from. It’s primarily sourced from surface water and groundwater. The specific sources can vary depending on the region and local water supply infrastructure. Lakes or reservoirs are one of the major sources of our drinking water, and figures about the levels of water in the dams varies week by week.

Many regions in Portugal obtain their drinking water from rivers and lakes. Water treatment plants are responsible for treating and purifying this water to make it safe for consumption.

Despite what many may think, tapping into the underground water reservoirs in the Algarve is now mainly limited to farmers and rural households who don’t have a water main connection. The government are trying to reduce the use of wells as much as possible, each has to be, in theory, licenced. With the lack of recent rainfall, many people report that their wells are running dry. Another factor is that neighbours may well be drilling new wells to find much-needed water.

The Algarve sits on enormous underground lakes. If you like a technical description, you can find it here. Essentially, the major aquifers of the coastal Algarve region were formed during two phases of extension of a meso-Cenozoic basin, forming aquifers that include karstic and fractured limestones of the Jurassic age, permeable limestone units of the Lower Cretaceous, sandy limestones of the Miocene age and sands and gravels of the Plio-Quaternary age. These form multilayer aquifers both within and across units, separated by lower permeability weathered clays and silts. To reach these underground deposits, it’s not unusual to have to drill down 150 metres.

Risky business

One recent problem is that seawater is leaking into many of these reserves when they are situated near the coast. This makes drilling for water near the coastline a risky business, and drilling for water is not cheap. The upside is that with the extensive development along the Algarve coast, nearly everyone has access to mains water, so wells shouldn’t be necessary.

In some coastal areas, desalination plants are used to turn seawater into fresh drinking water. This technology is especially important in regions where freshwater sources are limited. This is still very limited, not least due to the cost involved. It is however very effective, in the Madeira Island of Porto Santo, all drinking water comes from the sea and is collected in four galleries built under the beach. It has been this way for more than 40 years when it was decided to build a desalination plant to solve the scarcity of water resources on the island. This has the capacity to supply the 30,000 people who live on the island throughout the year, without any failure.

Desalination

In the Algarve, Vila Vita Parc uses a seawater desalination system to provide a sustainable water source for gardens and pools. The Portuguese authorities have selected Albufeira for the design and construction of a new seawater desalination plant that will provide water for the Algarve area of the country. The plans have been criticised by a local expert, a professor at the Faculty of Science and Technology of the University of Algarve, who said building not one, but two or three desalination plants in the region is essential.

Would the simplest solution be to enable rainwater which falls in greater quantity in the centre and North of Portugal to be shared with the Algarve? If dams in the North are almost full and the Algarve dams are nearly empty, it’s not rocket science to consider how to share this resource. Many dams are interconnected in the Algarve, but not with dams North of the Algarve.

This is not a cheap solution, but there isn’t a cheap solution, other than rainfall, and there is a lot more in the North of Portugal. Maybe it’s time to share. The government knows how to do it, is it too politically sensitive to consider?

The Algarve is a major source of income for Portugal, without good water this income will be at risk.

Author

Resident in Portugal for 50 years, publishing and writing about Portugal since 1977. Privileged to have seen, firsthand, Portugal progress from a dictatorship (1974) into a stable democracy. 

Paul Luckman