Area: 3059 ha
Biogeographic region: Turján-vidék
When containing an average amount of water, Lake Kolon is 5.5 km long and 1.5-2.5 km wide. It is a mostly reed-covered lake in a late successional phase; all of its open water surfaces are artificial. The average depth of the water is 1 m but at the former peat mining pits it has 2-3 m deep parts.
The homogeneity of reedy habitats is interrupted by some dredged clearings with open water (e.g. the former peat pits, two open patches created as part of habitat reconstructions, and the draining ditches). These open water surfaces are inhabited by White Water-Lily, Water Soldier and Greater Bladderwort. The lake gets shallower from north to south and the vegetation follows this gradient, as Grey Willow breaks the dominance of the reed. The shoreline is inhabited by Broadleaf Cattail but Tussock Sedge stands with good water supply can also be found here. The lake is surrounded by fen meadows and swampy hay meadows; their flower-rich vegetation reaches the peak of blooming in May. Military Orchid, Early Marsh-Orchid, Solitary Virgin’s-bower and Siberian Iris are among the common species. May is the blooming time of orchids, such as Bee Orchids. This species is very rare in the Danube-Tisza Interfluve but Lake Kolon still hosts a small population. Large Pink is rather abundant at some localities from mid-summer. The Közös Forest is embedded in these species-rich grasslands. This forest is an oak-ash-elm grove developed from an alder swamp forest and is considered the best-preserved representative of its kind in the Danube-Tisza Interfluve. On the western side of the lake, one can find the ragged Bikatorok Sand Dunes, which are covered by open sand steppe.
The diversity of habitats results in a rich fauna. Remarkable fish species of Lake Kolon include European Mudminnow and European Weatherfish. Frogs are abundant but European Pond Turtle and Grass Snake are not uncommon either. In the 1950-s, Hungarian Meadow Viper occurred in the wet grasslands around the lake but by now it has gone extinct. In contrast, Balkan Wall Lizard, Green Lizard and Viviparous Lizard, which is a relict from the Ice Age, are still widespread. Lake Kolon has been famous for its birdlife for long. The large confluent reed bed offers prime breeding ground for herons. Breeding conditions for Greylag Geese are improved by mosaic-like reed harvesting. A large number of songbird species frequent the reed bed in breeding season and also during migration. Common species include Moustached Warbler, Great Reed Warbler and Sedge Warbler. Besides the reed, wet meadows are also important bird habitats; geese, egrets, herons, lapwings and sandpipers frequent these habitats in large numbers. The ragged dunes on the western side of the lake are inhabited by species of forests and dry grasslands, such as European Roller, European Bee-eater and European Nightjar.