Drained lakes slowly coming back to life

Since antiquity man has tried to tame the force of water for his own needs, the oldest such project in Greece being undertaken in 3500 BC when Lake Kopais, near the town of Orchomenos was drained because of frequent flooding. Since then, dozens of lakes have been drained either to secure more farmland or to rid the area of flooding or disease-bearing mosquitoes. Over the years, however, nature has wreaked its vengeance. Dried lake beds were often found to be unsuitable for farming as they flooded in the first heavy rains, salt accumulated in the soil, and local fishermen were forced to turn their hand to farming, upsetting the balance in the local economy. Meanwhile the water table began to fall alarmingly and in some places the saline content rose. Other examples of human intervention in the natural environment, which were reversed decades later when locals realized what they had lost, include the Drana lagoon in the Evros Delta, Lake Karla in Thessaly, Lake Mavrouda in Arethousa and Askouris Lake in the mountains at Kallipefki, Larissa. «It is believed that large bodies of water act in areas to reduce summer temperatures and raise winter temperatures,» said Dimitris Papadimos, an irrigation expert at the National Center for Biotopes and Wetlands. Draining a lake results in the loss of a natural means of flood protection. «Local water systems act as a kind of natural filter for the water,» he said. «After passing through these ‘filters,’ any water that spills over into adjacent cultivated fields is clean. If there are no wetlands, the water is basically untreated.» He added that draining a wetland also means a loss of cultural heritage with the disappearance of a range of related occupations, such as boatmen, boat builders and basket weavers. «Also lost are educational and scientific values that these systems offered from the point of view of biodiversity and physical and chemical processes.» Local communities have come to realize past mistakes along with the value of wetland systems for recreational purposes and alternative economic use. Drana lagoon in the Evros’s lower delta, the largest and most productive lagoon in the Aegean, covered 1,000 hectares in the 1950s. Damming, canals, embankments and irrigation works soon reduced this area, upsetting the balance between fresh and salt water in favor of the latter. An embankment built to prevent salt water entering neighboring fields reduced it to 600 hectares by the 1960s, when the embankment collapsed and saltwater flowed into the fields. Angry farmers built a dam blocking access to the sea; the lake dried up and the water table fell. In 2001, local authorities and residents, with the help of the European Union’s «Life» program, began to restore the embankment and islands, once a breeding grounds for birds, and created a better water flow within the lagoon. In June 2004, access to the sea was restored. The next plan is to restore the lagoon’s supply of fresh water.