Drained in 1962 to combat malaria and restored again from valley to wetlands in 2018 to remedy drought, the lake is now triple its normal size after deadly floods last year.
How to deal with the aftermath of the disaster has morphed into a debate about the future of farming in the Thessaly region as a whole.
The farmers around Karla, many the descendants of lake people who had transitioned to land only two generations earlier, saw their holdings and flocks decimated by last year’s floods.
In September, Storm Daniel, a Mediterranean cyclone of unprecedented intensity, unleashed months’ worth of rain in just hours on Thessaly, Greece’s most fertile plain.
The deluge, which killed 17 people, destroyed roads and bridges and drowned tens of thousands of farm animals.
Daniel, which arrived on the heels of a major wildfire wave, was followed just weeks later by Storm Elias. Combined, they triggered what Prime Minister Kyriakos Mitsotakis later called “the worst floods” in Greek history.
The lakeside village of Sotirio, once bordered by fields of corn and cotton, now lies at the edge of a swamp. Dark green water buzzing with insects covers the fields. Even where the flood has receded, only silt and withered stems remain.
Angelos Yamalis, a third-generation farmer, said his family lost 50 hectares (120 acres) of cotton, 30 hectares of wheat and 15 hectares of pistachio trees.
“It was a complete disaster … Even after the water recedes, we don’t know if the fields will be productive,” said the 25-year-old.
“We based our entire future on this area, on these crops,” Yamalis said, adding that new trees would need at least seven years to bear fruit.
Officials have not provided a timeframe for recovery and there are conflicting views on how to move forward. The authorities in Thessaly favour digging a large canal that would let the water drain into the Aegean Sea.
But a Dutch water management company advising the Greek government advocates a different approach, aimed not just at stemming floods but also at preventing future drought.
The firm, HVA International, suggests building dozens of small dams that would contain rainwater in the mountains.
Thessaly also needs to rethink its reliance on cotton, said Miltiadis Gkouzouris, CEO of the Amsterdam-based firm. The region needs to move away from cotton production while there is still time to conserve what remains of its underground water reserves, he said.
Greece is the European Union’s main cotton grower, with 80 percent of production. Although cotton represents less than 0.2 percent of the value of European agricultural production, it has “strong regional importance”, the EU says.
Gkouzouris countered that cotton cultivation “on its own is not profitable and everybody knows that”.
“We calculate that if that continues with the rhythm that we have today, within 15 years we’re going to have a non-reversible situation,” he said.
Thessaly’s Governor Dimitris Kouretas is against ditching cotton, still a lucrative industry for residents.
Kouretas, a Harvard University-educated biochemistry professor who was elected governor in October, has argued that cotton brings 210 million euros ($227m) in revenue to 15,000 families in Thessaly and is a key export for Greece. An additional 65 million euros comes in EU subsidies.