Lorraine Williamson
For decades, Valencia’s Albufera lagoon has been celebrated as one of Spain’s most emblematic wetlands. Yet new findings suggest the jewel of the Mediterranean is now facing a far deeper crisis than even the Mar Menor in Murcia — long seen as the country’s most notorious environmental disaster.
Juan Miguel Soria, a veteran biologist at the University of Valencia who has studied the ecosystem since the 1980s, says water samples show shocking results. Chlorophyll levels — a marker of algae caused by agricultural run-off — are around 200 in the Albufera, compared with just 2 in the Mar Menor. In practical terms, that makes the lagoon roughly 100 times more polluted than its southern counterpart.
The culprits are well known: nitrogen and phosphorus from intensive rice farming around the lagoon, and fertiliser residues carried in from irrigation networks further inland. Unlike the Mar Menor, the Albufera has limited renewal of its waters. With just three narrow channels linking it to the Mediterranean, exchange is rare and usually only when levels rise after heavy rainfall.
A fragile ecosystem under strain
Environmentalists have long warned of the lagoon’s precarious state. The Albufera covers 2,500 hectares but has effectively been in decline since the early 1970s, when untreated sewage from surrounding towns was discharged into its waters. Although direct wastewater dumping ended years ago, the pressure from agriculture has continued.
Soria notes that the lagoon has not seen clear water since the summer of 1972. He now calls the Albufera the most polluted coastal lagoon in Spain and the third worst in the entire Mediterranean basin.
Floods offered temporary relief
Ironically, one of the most devastating storms in recent years provided momentary respite. When torrential rains struck Valencia in October 2024, more than a million tonnes of sediment poured into the lagoon, raising the bed by several centimetres. The surge flushed huge quantities of algae and nutrients out to sea. Soria likened the effect to “flushing a toilet”.
But he warns that unknown substances may have settled into the new layers of sediment, leaving longer-term risks still to be assessed.
Albufera Valencia cleared after removal of 2,500 tonnes of waste
Climate change adds new danger
Rising global temperatures and sea-level increases now threaten to tip the lagoon into irreversible decline. A rise of even one metre could allow seawater to mix with the freshwater system, destroying the delicate balance on which the wetland depends.
Protected but not safe
The Albufera has been a natural park since 1986 and is listed both as a Ramsar wetland of international importance and part of the EU’s Natura 2000 network. These designations underline its value for biodiversity, particularly migratory water birds.
Yet the protections have done little to halt ecological decline. Experts argue that without a radical shift in agricultural practices, combined with stronger environmental safeguards, Spain risks losing one of its most treasured natural landscapes.
A call for decisive action
The plight of the Albufera highlights a broader challenge for Spain: how to balance farming traditions with environmental protection. As the Mar Menor edges towards recovery after years of ecological collapse, attention now turns to Valencia — where the country’s next major environmental battle is already underway.
Source: El País