Ash from summer fires is now poisoning rivers

The people of Ourense, the Bierzo region and northern Cáceres have seen it up close: rivers of ash falling from the mountain like a silent avalanche. In some towns The tap water is no longer drinkable, and a brown liquid leaks from the fountains.. “We warn about this and it seems hard to believe, but fires don’t go out when the fire stops,” recalls Victor Risco, a forest engineer and professor at the University of Lleida. “The consequences last for months or even years.” Toxic rivers are the first sign.

A “chemical cocktail” for health

Risko explains to ABC that the sewage problem is not only visual, although it is the most striking, as this withdrawal can have “extremely negative effects on water quality,” especially in surface water, on which rivers, reservoirs and entire populations depend. Rivers became a “chemical cocktail”He says.

The particles emanating from the burning mountains carry heavy metals such as arsenic, lead, mercury, and the remains of organic materials. “These compounds infiltrate aquifers and, when ingested, can cause chronic toxicity,” he warns. It can lead to damage to the nervous system, kidneys, or liver. In addition, water treatment plants are overcrowded due to increased turbidity and biomass.

Dead animals and plants

But the problem does not end there. The ash also impoverishes the rest of the life forms – animals and plants – that are part of the ecosystem and that depend on the poisoned water. The impacts on these river ecosystems are immediate. in the channels, Ash suffocates fish and invertebrates By clogging the bottom and reducing dissolved oxygen. They also change the pH and release nutrients that lead to toxic algal blooms and cyanobacteria.

In addition, heavy metals stick to fish tissue, potentially poisoning birds and mammals that feed on them to survive. Plants growing at the bottom of rivers die from lack of light and oxygen, breaking the entire food chain in the process. “If you lose the plants there will be no insects, without them the fish disappear, and if the food runs out, the otters and herons die,” explains Miguel Angel Soto, spokesperson for Greenpeace Forest Campaigns, who wants to make it clear that “Water is not what is drunk or used, neither for people nor for animals.”.

“Skeleton” terrain.

Added to this is the loss of quality Land degradation. Soil, devoid of plants, loses nutrients and becomes more “skeletal,” delaying the natural regeneration of both forests and crops. “The fires have wiped out soil-bearing plants, and without this natural shield, erosion rates would skyrocket,” Risko explains. When heavy rains fall, this mixture of sediment and ash settles into riverbeds, polluting reservoirs and springs. “Without the large burned area, areas with high slopes and heavy rains, this would not have happened,” Soto adds.

Experts sum it up in one phrase: the perfect storm. Although toxic concentrations will weaken as the weeks pass, the immediate impact is serious, especially in villages and small towns that depend on rivers or springs for their drinking water supply.

In Galicia, the most affected area is Valdeoras area (Ornesses), scene of the largest fire in the community’s history, destroying 30,000 hectares this summer in the municipality of La Rocco. In areas like Petén, residents have been forced to take on prevention and containment tasks due to a lack of resources. “The situation changes day by day, depending on the rainfall. “At some points, the water becomes dark, although in general it is not as dangerous as Villamartín de Valdeoras,” explains the city’s mayor, Raquel María Bautista.

“It is not suitable for drinking, but it is intended for use in washing machines or showers,” Bautista admits, denouncing the absence of protocols and the lack of coordination between departments. “We do what we think is best,” he says. For its part, Xunta de Galicia has announced the construction of embankments, plant cordons and the use of straw or motherwort to stop erosion – “mulching” or “gel-coating” techniques when applied from helicopters – although a lack of communication with the Minno Sil Hydrographic Consortium has again caused the usual occurrence of erosion. Intersection of accusations about competenciesWhich in the case of these preventive tasks relate to Galicia in the mountains and the central government in the river basins and reservoirs.

For Professor Agustín Merino, an expert in soil science and agricultural chemistry at the University of Santiago, the problem is two-fold: The size of the fires and the cost of restoring what was burned. “In large fires, between 10 and 15 percent of the surface is extremely dangerous. “This is where these techniques should be applied, but in Galicia they have only been applied to 1% of the affected lands,” he warns. With the Ourense River’s steep slopes, runoff multiplies, and so do the risks. “The cost of cleaning up this water will be enormous,” he warns. In addition, he warns of what is to come. “The greatest danger will come in summer, when the nutrients carried by the ash become a breeding ground for cyanobacteria. “With the heat, toxic blooms will appear, making the water unfit for consumption and even for bathing.”

In Birzo, neighbors also live watching the taps. In Puente de Domingo Flores, a small town of 900 inhabitants, and in Salas de la Ribera, with 250 others, Municipalities have banned the consumption of tap water Until further notice, they are placing large deposits on the streets. Each neighbor fills his jugs as he needs, and when they run out, the cisterns refill them. Kilometers away, in the Lamas de Cabrera watershed, fire has destroyed plants that protected the soil and now leaves a gray seal in the water.

In Tremor de Arriba, an area of ​​the municipality of Igweña, residents have been unable to drink from the tap for almost two months: the fire destroyed eight kilometers of supply pipes, and autumn rains filled the Tremor River with ash. At the request of the neighborhood council, the Lyon District Council distributed bottled water to residents. In other affected municipalities, city councils They have stepped up water analysis In case it is necessary to restrict consumption.

In Extremadura, the impact of fires and rain has been devastating. According to forestry expert Paco Castañares, the most affected areas are located around Jarilla and Las Hurdes, where fires this summer reached the peaks that originate from the Ambrose and Jairti rivers. “Throats are dead. No life is possible in them.warns. “The soil had a very thin fertile layer and was completely bare. Without roots to support it, the rain drags it down the slope. “This loss prevents the natural regeneration of the forest and it can take centuries to recover. Today, many towns in northern Cáceres receive water in cisterns, “as was the case in the 1960s,” Castañares says sarcastically.

Experts say fire, water and erosion have the same diagnosis: an unmanaged and undefended area. “We have to invest in green restoration, not black restoration,” Risco insists. They advise allocating resources to prevention – managing forests, maintaining large-scale livestock farming, clearing forests, implementing controlled burning and encouraging agriculture – rather than spending millions after a disaster.

Experts agree that rivers of ash that descend after rainfall are only the most obvious symptom of a structural problem. Spain burns every summer, and when the fires go out, the landscape continues to burn from within.