The death of a lake in Greece

The people of Agios Vasileios are haunted by an absence. They talk about it to anyone willing to listen.

"I can't even describe the beauty of going out to fish with my father to my children," says Dimitris Frangoudis, a retired port authority officer.

"We used to live off the lake, and we lived well. There was fish and money," says a middle-aged local woman.

Pantelis Koutsakis, a restauranteur, recites the names of the fish he used to catch with the nostalgia of lost youth: Grivadia, pyrkia, syrka, tournes, tsironia, listia, gerbalikia.

Lake Koroneia, 30km east of Thessaloniki, is no more; at least not the way locals like to remember it. Five decades of mechanised irrigation and industrial development have killed a body of water that has lapped the shores of Agios Vasileios since ancient times. A Byzantine watchtower in the heart of the village testifies to the antiquity of the waterline.

A case study

Koroneia's demise - and current efforts to restore it - showcase what is happening to water systems across Greece.

Human pressures on the ecosystem began innocently enough. Fishermen occasionally became greedy; locals describe the gripos, a banned fishing method whereby a large net was stretched between two boats and rowed to shore, trapping large quantities of fish.

Revenue from fishing was supplemented by farming - a traditional enemy of lakes and wetlands in Greece. The General Organisation of Yield Improvement (GOEV), set up in 1959, rented exposed lake bed for locals to cultivate in dry years. That gave it an incentive to drain the lake by widening a natural outflow channel on its eastern edge.

Farms around the lake are now dotted with breezeblock pumping houses sucking up groundwater. The water table has receded enough that it no longer feeds into the lake, experts say. Rather, the lake bleeds into it.

Reduced rainfall has finished the job. Seen from the height of Mount Hortiatis to the south, Koroneia appears like a half-empty swimming pool. Roughly a thousand hectares of damp mud form its western edge.

A 2004 master plan drafted by a team of academic researchers estimated that the lake's water volume had dropped to 20 million tonnes in 1996 from 130 million tonnes in 1986 a decade earlier.

1996 was also the year in which rising pollution fatally compounded the problem of falling water volume. "Everything died. Nothing was spared... Bugs, frogs, everything. There was a stench of thousands of rotting fish," remembers Koutsakis.

"The cause was the lack of oxygen in the water," says Yiorgos Zalidis, a professor of soil science at the University of Thessaloniki who led the 2004 research. Chemical nutrients from fertiliser and untreated sewage from the nearby town of Langadas had created algal blooms that deoxygenated the water. Ten years later pollution would strike again, this time in the form of botulism, which killed hundreds of migratory birds.

Even if oxygen levels were restored, fish could not inhabit Koroneia due to its alkalinity. A dairy plant owned by Agno periodically cleans out its machinery with caustic soda, leaving the effluent untreated, locals say.

The biggest industry around the lake in the 1970s and 1980s was textile dyeing. About two dozen factories pumped thousands of tonnes of salt a day into the lake, and have left it with a sediment rich in heavy metals.

"People didn't know the danger," says Frangoudis. "One time I found my father casting his nets in the outflow of the dyeing factory to clean them in the chlorinated water. I asked him what he was doing. He said he was catching fish and cleaning his nets at the same time.

"No one spoke up because [the plant] hired more than 500 people, 300 from the village," he says.

"Some dyeing plants had chemical filters but they didn't turn them on," says Koutsakis, whose brother owned one. "They would be fined and never pay."

Frangoudis cast his last nets into the lake in the early 1990s, he says. "It was clear that fishing was no longer something a person could live off."

A glimmer of hope

A major effort is now underway to restore Koroneia to something resembling its former glory. Massive excavators are broadening a natural trench connecting it to Lake Volvi, four kilometres east. The idea is to use the trench as a regulator. When Volvi overbrims, it will channel the excess water to Koroneia.

"I'm often asked whether the situation is reversible," says Zalidis, whose brainchild the trench is. "Restoration here doesn't mean going back to what we had before. It means going to a self-sustainable state. You're not going to have the pre-1995 lake again. We couldn't make a Koroneia covering 4,500 hectares. We can do 3,500 hectares."

Zalidis' master plan is complex. Apart from the trench, it calls for a dredging of parts of the lake to form deep spots. That way, says Zalidis, parts of the lake will sustain life even in dry years. The dredged mud will form a six-kilometre long bank helping to define the lake's shore.

Another provision is the creation of four wetland areas in the lake's shallow western end to help sustain a full ecosystem.

If all this is done, the lake should expand and achieve a depth of four metres - a far cry from the current 40cm. But the project will not be a panacea if people don't change their ways, Zalidis says.

He has recently taken over as scientific director of the Balkan Environment Centre based in nearby Langadas. From that vantage point the view is disappointing. "Nothing makes me optimistic... the causes of degradation continue," he says. He has no explanation for why Langadas refuses to truck its sewage to a treatment plant built for the purpose, but lying idle.

Paradise will not be regained for the people of Agios Vasileios. The lakeside promenade they built in 1982 will remain a dry monument, hundreds of yards from water. A smaller lake will not support the volume of fish that used to go through their now derelict weighing station. As construction takes over as the area's main industry, catering to flight from Thessaloniki, the handsome vessels they used to fish in with their optimistic prows and black with pitch like Homer's ships will probably never be rebuilt.

But Zalidis sees the Koroneia master plan as a pilot project for other Greek lakes, many of which have suffered similar human pressures: "What is at stake in this restoration is whether different authorities can agree to a different development model to that which has destroyed us until now."

John Psaropoulso writes for Athens News from which this article was adapted.