NATURAL SPACES | The extraction of groundwater suffocates Doñana

Doñana is dying. The extraction of groundwater for intensive agriculture is the main cause of the serious impacts recorded in the largest wetland in Europe. A scientific team led by the Doñana Biological Station (EBD) and the Mining Geological Institute, both centers of the Higher Scientific Research Council (CSIC), has reviewed more than 70 studies related to the underground water and the conservation status of Doñana and has shown that there is “a ample scientific evidence of the serious impacts caused by the excessive extraction of water from the aquifer“.

The data from the Guadalquivir Hydrographic Confederation “demonstrate a general decrease in groundwater levels throughout the protected area over the last three decades and, especially, in the areas closest to the areas of water extraction for agricultural use and urban consumption“.

Along with them, according to the EBD analysis, there have been “numerous” scientific studies carried out in recent decades that have confirmed the existence of “impacts” on aquatic and terrestrial habitats from Doñana, as well as the quality of its waters.

Birds resting in the Santa Olalla lagoon, in Donana. EBD/CISC

“Since the seventies, different scientific and technical voices have denounced and continue to denounce that Uncontrolled extraction of groundwater would have very serious consequences for Doñana“said Carolina Guardiola Albert, CSIC researcher at the Geological Mining Institute of Spain (IGME-CSIC). “It is inevitable to have the feeling that The water and territory managers involved in this area at all levels have not listened to these complaintsor if they have heard them, they have not been able to take effective action,” he added.

“Clear and abundant” impact

As highlighted by the CSIC; during years “No measures have been put in place to avoid, or at least mitigate, these impacts on the protected space.“In fact, the Court of Justice of the European Union (CJEU) even condemned Spain in 2021 for this reason. And a year later, it again threatened with a new conviction if an agreement was not reached to withdraw the proposal. of law of the Government of Andalusia that sought to expand irrigation in the area of ​​Doñana.

“The actions of the CJEU represented a change in attitude, but we remain skeptical that the necessary measures will be implemented and, above all, that all the administrations and agents involved will be coordinated to execute these measures effectively,” he said. commented the scientist.

The impact that agriculture is causing in the surroundings of Doñana is “clear and abundant”. The EBD assures that there are “several studies” that show “how lThe reduction in groundwater levels has led to the disappearance of many lagoonskeys to the conservation of many species”.

In one of the studies reviewed, published in 2001, “a drop in the water table between 1972 and 1992 of up to 20 metersas well as the disappearance of lagoons that had been recorded on historical maps, especially in the northern area, the most affected by the decrease in groundwater due in part to irrigated rice crops.

More recently, in a study published last year, the Doñana Biological Station identified “a loss of almost 60% of the gaps that existed in the 80s“.

Intensive agriculture, guilty

The vast majority of lagoons fill less and dry out sooner than expected due to the climateespecially in the areas closest to Matalascañas and the greenhouses, which reveals the impact that the overexploitation of the aquifer is causing,” so this “affects numerous species of animals that depend on the existence of bodies of water in their reproductive season, as well as aquatic vegetation.

Strawberry cultivation farm located in the irrigated area north of the Doñana Forest Crown. EFE / Julián Pérez

On the other hand, the EBD has explained that the extraction of water from the aquifer is also having “strong impacts” on the marsh. Along with precipitation, the surface water flows that reach the marsh receive discharges of water from the aquifer.

However, these “have been reduced in recent years”, as pointed out by several studies carried out in the Rocina area in the early 2000s, which suggest “a 60% reduction in groundwater discharge to the flows that circulate through the area.” In fact, the EBD points to “the great expansion that intensive agriculture has experienced in the area” as the cause, along with “the reduction of water drainage from the aquifer at other points.”

This “impact” has also been on terrestrial vegetationas explained, since centuries-old cork oaks “are dying at an incessant rate8% of them have already perished since 2009 and many are losing their leaf cover due to falling water tables.”

On the other hand, Water quality has also been affected.since, as indicated by Andy J. Green, CSIC research professor at the Doñana Biological Station, “although we usually talk more about the quantity of water, about contributions, than about quality, the truth is that they are just as important “, since The polluting contributions to the marshes “have been increasing with agricultural and urban expansionespecially in the area of ​​El Rocío”, as several studies point out.

Toxic algae and invasive plants

“Soft fruit crops for which water is extracted depend largely on the agrochemicals, which in turn are transferred to groundwater and surface water. A reduced flow in the marsh also leads to a greater increase in pollutant concentrations and salinity through evaporation,” they explained.

On the other hand, they have also pointed out that Climate change, with rising temperatures, “is favoring the proliferation of toxic algae and invasive plants by this type of nutrients”. It has been detected, for example, “a considerable increase in phosphorus load since 2000, which has favored the expansion of the invasive aquatic fern Azolla filiculoideswith serious impacts on amphibians and aquatic plants”.

Water conduction on a farm in Doñana where strawberries are grown. EFE / Julián Pérez

“We have turned the national park into a green filter to clean the waters of the streams, which are often already toxic to fish and other fauna,” said Andy J. Green, while pointing out that The contamination of the Doñana aquifer “due to agricultural and urban activities dates back to the initial expansion of irrigation in the 1970s and has been recognized by international institutions”, so “Measures are urgently needed to reduce the entry of fertilizers into the aquifer and clean the waters before entering the National Park”.

One of the measures that is usually proposed is to carry out water transfers from other basins close, but the scientific team considers, however, that it is a “unrealistic” proposal to restore the state of the aquifer”, since “there is little surface water available in the region and the climate models proposed for the future in southern Spain are not favourable”.

“Besides, The transfer of water from other hydrographic basins could facilitate the arrival of invasive species and promote eutrophication processes. associated with the expansion of irrigated crops, as has been observed in the Mar Menor”, they concluded.

Reference report:

Post Comment