TonTo a casual observer, the Ebro Delta appears to be in good health. There was gurgling water in the canals and irrigation channels, and there seemed to be a mighty river flowing into the sea. The dazzling green rice fields are dotted with ibis, egrets and red legs.
However, everything is not what it seems. The Ebro River is one of the only rivers that flow into the Mediterranean among the three major rivers in Spain, and it is also one of the most abused and exploited rivers in Spain. Europe.
It originated in Cantabria in northern Spain, and its waters were interrupted along its 910 km (560 mi) route. Extracted by 70 dams Before it discharges into the Mediterranean in southern Catalonia, it is actually exhausted.
More than 90% of the sediments, the lifeblood of the delta, provide food for offshore shellfish and fertilize rice fields, build dams upstream, and never reach the sea.
“In a healthy delta, there is enough sediment to cope with rising sea levels, even with climate change,” said Maite Martínez-Eixarch, a biologist at the institute. Institute of Agricultural Food Research and Technology (IRTA), Located in Sant Carles de la Ràpita in the Delta. “This is part of the natural system. But 99% of the sediment is captured by the dam.”
Ebro is the canary in the climate crisis, equivalent to the canary in the coal mine. From rising sea levels to invasive species, estuaries and river deltas can serve as early warnings of bad things.
Spain’s east coast is soft and consists of sand dunes and mudflats. In areas such as the Ebro Delta, not only is the sea level rising, the land is also sinking. Approximately 70% of the deltas are only 50 cm (20 inches) above sea level, and as the sea level rises and there is no sediment to stop it, the sea is gradually expanding, eroding the coast at a rate of 5 meters per year.
Mike Elliott, professor of estuary and coastal sciences at the University of Hull, said: “You have lost natural habitats such as salt marshes and seagrass beds. When these natural habitats are removed, the system will lose some Resistance and resilience.”
Estuary is also particularly vulnerable to what Elliott calls the “triple blow”, that is, increased urbanization and industrialization, increased use of resources (space, fish, water, etc.), and decreased resistance and adaptability to climate change.
Pilar Marcos, a biologist and biodiversity coordinator at Greenpeace, said: “These areas have usually been built in large numbers and usually do not comply with zoning regulations.”
For the Delta, global warming has exacerbated a long history of abuse and neglect that lasted for half a century.
Martínez-Eixarch colleague Xavier Benito said: “It is not so much climate change as it is global change, because it is also related to the over-exploitation of rivers. The delta is the place where all these effects are most felt.”
Nowhere is coastal erosion more felt than Riumar at the mouth of the estuary.
“This is the most vulnerable part of the delta where the river meets the sea,” said Eutimio Mauri, chairman of the Riumar committee. He said that if action is not taken as soon as possible, Riumar’s 700 citizens may soon become one of Europe’s first climate refugees.
According to EU directives, the Spanish government is obliged to protect the delta and will announce its long-awaited rescue plan next month.
From what little is known about these proposals, the plan is actually to create a new coastline 280 meters inland from the current limits. Sand dunes will be built to block the sea.
However, in the process, 422 properties including houses and restaurants will have to be abandoned. The plan was not welcomed by local resident Juan Miguel Belloubi.
“Besides, if there is another storm like Gloria, the dunes will not last a day,” he said. In 2020, storm Gloria swept through the slender defenses of the delta, pushing the sea three kilometers inland. Destroyed thousands of hectares of rice fields.
Mauri prefers to use submarine smart breakwaters, which is a plan favored by the local government. Martínez-Eixarch also stated that IRTA has devised a pilot program to siphon sediment-which is a problem for power companies because it will block the dam-and allow it to flow back downstream where it belongs.
But she believes that there is no single answer to this question.
“We need solutions based on nature,” she said. “Dykes will help in the short term, but they are expensive. Protecting sand dunes and restoring wetlands will be natural ways to prevent erosion and a more effective mid- to long-term solution. They can also improve water quality and increase biodiversity.”
Climate change and international shipping have also brought unwelcome tourists to the Delta in the form of several invasive species. Among them is the greedy blue crab (Callinectes sapidus), A species native to the eastern United States with Almost wiped out the local crabs.
Other American invaders-red swamp crayfish (Procambarus clarkii) And island apple snail (Macularia)-Threaten the important rice farming industry in the area.
On the other side of the country, on Spain’s Atlantic coast, the mouth of the Galician estuary, known as Rías Baixas, is also plagued by invasive species.
More than half of the 400,000 tons of mussels consumed in Europe each year are produced in Galicia and the Ebro Delta.
At the Ría de Arousa, the largest estuary in Galicia, a conch (Pasqueflower) Originated in Japan, it usually feeds on oysters. It has a diverse diet and is now devouring mussels and clams.
Local biologist Alexia Costas said that snails can eat 3 kilograms (6.6 pounds) of shellfish a year. Mussel farmers have collected nearly 150,000 mussels, otherwise they would consume 450 tons of crops.
Elliott said the reason why the estuary is so fragile is the balance between the river and the ocean. “Anything you do that interferes with this connection will crash the system.”
However, despite this, Martínez-Eixarch and Benito are still optimistic, citing the increasing public awareness and political will to seek solutions.
“The delta is a complex system because there are economic benefits, such as rice growers, fishermen, and tourism, and then ecology,” they said.
“But we think we can find a solution that suits everyone.”
