Intensive farming “poisoning Alentejo reservoir”

But law “does not allow local authority to act”, says deputy mayor

The water of the Maranhão reservoir in Avis has a dangerous amount of cyanobacteria, which can be fatal for livestock, a situation that is worrying the local authority, which points its finger at intensive farming.

The alert has been sounded to Lusa news agency by Luís Teixeira, owner of a tourist resort near the reservoir. He has supplied photographs and videos of the water, with light blue stains of a pasty and unidentified product. He blamed the intensive olive groves around the reservoir, constantly sprayed with chemicals that end up in the water.

Avis deputy mayor, Inês Fonseca, who is in charge of tourism, told Lusa she fears the council will have to prohibit water sports in the reservoir.

“Agriculture is important, but we have to ensure that all activities are compatible,” she said, suggestimg the olive groves are compromising investments made in sports like rowing, canoeing, triathlons, even open-water swimming.

There is another problem too: Fonseca says the local authority has spoken with the olive farmers “but they said they were not to blame”.

The council has done everything to eliminate any type of discharge into the reservoir, ditto parish councils (which all have water treatment plants). Thus Avis deputy mayor “has no doubts that the problem of cyanobacteria arose with the appearance of intensive agriculture, namely the olive groves, where “many fertilizers” are used that end up in the water when it rains”, says Lusa. 

A delegation from the Portuguese Environment Agency (APA) has equally confirmed the existence of cyanobacteria (also known as blue algae) in the water, while the National Institute of Health Doctor Ricardo Jorge analysed water taken from the middle of the reservoir “about a fortnight ago, and the result was the same. A biologist wrote in a document seen by Lusa that “the concentration of microcystins (the toxin from Microcystis aeruginosa) was so high that even with maximum dilution, it was not possible to measure”.

The specialist warned that the water “is potentially dangerous” and that for livestock, which drink large quantities of water, it could be lethal because microcystins (toxins produced by cyanobacteria) are hepatotoxic (produce liver damage).

Inês Fonseca told Lusa that the council has also contacted health authorities which are now going to analyse the water.

“We’re reviewing the Municipal Master Plan (PDM). We had a meeting with the Directorate-General of Agriculture, we wanted to set up a safeguard area for this type of agriculture, but they told us there is no way of preventing intensive agriculture, because the law does not allow it”, she said.

Fonseca went on: “People complain, that there’s a white product on the ground that sticks to cars, to houses, everybody complains, but the town council can’t do anything, it has no answers to give. Our idea was to try and limit agriculture in the PDM. I would be very sorry if we were prohibited from practising water sports in the reservoir, which is the anchor of tourism in Avis”.

Luís Teixeira, owner of a water sports resort near the dam, would also be badly affected if this happens, says Lusa: “A sportsman himself, he began rowing in the reservoir at the age of 16, took part in nine rowing world championships, and in 2009 built his hotel, which hosts training sessions for many international teams”.

Teixeira told Lusa that the water has been affected by blue algae since 2018. The only change in recent years has been environmental, with the planting of intensive olive groves around the dam.

He believes it is urgent to solve the problem of the Maranhão reservoir. APA has “done nothing, neither in past years nor in this one”. In 2020, he said, the problem was communicated in May; APA responded in October. “No action was ever taken, and the situation has only been getting worse.” In fact now there is a bad smell near the water…

Luís Teixeira even believes there is “a lack of will to resolve the problem” and that authorities are stubbornly ignoring what is happening to the water in Maranhão.

“I cannot listen to claims that we are the leaders in decarbonisation when on the ground the situation is like this,” he told Lisa.

For José Núncio, president of the Association of Sorraia Valley Irrigators, “the situation is not new, unfortunately, and appears with high temperatures and then disappears.

Núncio doesn’t deny that olive trees could be one of the origins of the problem, but adds: “these are old reservoirs, which are undergoing a process of eutrophication. It’s 67 years of mud, and the olive groves take little water”, he says, hoping that ‘within two or three days the latest situation will normalise’.

His association brings together 1,800 farmers – beneficiaries of Maranhão and Montargil dams – the latter not having these problems.

José Núncio adds that cyanobacteria has no effect on irrigation, which is starting now, but he warns that bathing near the blue foam can be dangerous to the skin.

LUSA