Saline and alkaline
Between Szabadszállás and Akasztó on the deepest parts of the former deep water line of the flood plain of the Danube are the chain of sodic lakes and sodic marshes run north and south. These lakes are the Zab-szék, Kelemen-szék, Szántó-szék, Pipás-rét, Kisréti-tó, Fehér-szék, Büdös-szék, Csaba-rét and the Böddi-szék.
The sodic lakes were formed in the silted up depressions of the ancient Danube riverbeds. Before the river regulations the Danube frequently flooded the area of sodic lakes in the Valley of the Danube, but in these days they only can get their water supply from the precipitation and from the high salt content groundwater flowing here. The sodic waters are first of all rich in sodium and bicarbonate ions and they are also highly alkaline because of their soda content. During the most droughty period the beds are completely dried up and the concentrated dissolved salts are precipitated in crystals form on the surface, giving a white colour to the landscape. Close to the surface, as a result of the high salt content groundwater, calcareous-sodic solonchak soils were developed. The surroundings of the sodic lakes’ surfaces are seemingly monotonous, because they are divided by microreliefs, like salty patches with slowly moving surface water (szikfok), alkaline benches (szikpadka) and blind salty patches (vakszik).
After the Second World War in the spirit of the comprehensive utilization to make the Lake-Kelemen productive, fish pond systems were planned. In 1967 as a side branch of the Kígyós-ér – transformed into main irrigation channel (Kiskunsági-főcsatorna) – the three km long overground (elevated) feeder channel - planned on the Kelemen-szék and Zab-szék - leading through between the two lakes was ready as a part of the more than 500 hectare fish pond system. The continuation of this is a deep drainage ditch which could empty the water of the fish ponds into the Dunavölgyi-főcsatorna (Main Channel of the Danube valley). But fortunately, due to the establishment of Kiskunság National Park in 1975 the complex development of the pond system was prevented.
The high banks (about 0.4-1.65 metre) of the closed, never putting into operation channel, markedly stood out from the open perfect plain surface and besides the fact that the banks hindered the natural surface water movements they represented negative effect on the landscape as well. The banks of the large cross-sectioned feeder hindered the surface water movement and they changed the runoff conditions on the inconspicuously sloping relief as well. The major ecological problem was related to the previously coherent uniformly altering habitats’ isolation by the banks. The survival and development of the alkaline benches (szikpadka), alkaline flats (sziklapos), abrasion shorelines –were formed by the surface water as well - as geomorphological value depend on the permanence of surface waters and their runoff conditions.
The last problem, the feeder of the onetime ambitious plans - being harmful to the environment - was managed to eliminate in the framework of Environment and Energy Operative Programme of New Széchenyi Plan (KEOP) in 2014. In the course of the works the three km long large cross-sectioned feeder was terminated so that the residual surface forms could greatly resemble to the original. The removal of the artificial establishments has resulted in a positive impact on the values of surface morphology as well by the alteration of water flow into natural direction. In addition to the ecological reasons the enhancing of aesthetic values of the landscape, the landscape rehabilitation is outstanding as one of the special objectives of the project. At the area around the Kelemen-szék the landscape character is the “puszta” (Hungarian steppe) with specious horizon offering a view of the whole area, which is a unique landscape value. By the elimination of the standing out channel from the area the original steppe (puszta) landscape can be admired again. As part of the project a nature trail, a parking place, a resting place and a bird observation house were established as well.
sodic lake in spring time