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Response of the Karst Phreatic Zone to Flood Events in a Major River (Bohemian Karst, Czech Republic) and its Implication for Cave Genesis
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SYSNO ASEP 0379856 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Response of the Karst Phreatic Zone to Flood Events in a Major River (Bohemian Karst, Czech Republic) and its Implication for Cave Genesis Author(s) Vysoká, H. (CZ)
Bruthans, J. (CZ)
Žák, Karel (GLU-S) SAI, RID, ORCID
Mls, J. (CZ)Source Title Journal of Cave and Karst Studies - ISSN 1090-6924
Roč. 74, č. 1 (2012), s. 65-81Number of pages 17 s. Publication form WWW - WWW Language eng - English Country US - United States Keywords karst ; cave genesis ; Bohemian Karst Subject RIV DB - Geology ; Mineralogy R&D Projects GAP210/10/1760 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z30130516 - GLU-S (2005-2011) UT WOS 000306881100007 EID SCOPUS 84865450447 DOI https://doi.org/10.4311/2010ES0178R Annotation Hydraulic and hydrochemical relationships between a medium gradient river and a karst aquifer were studied by water level and temperature logging combined with water geochemistry and delta C13. The cave lakes are separated from the river by a floodplain up to 150 m wide formed by a gravel and sand layer up to 13 m thick covered with fine-grained floodplain sediments. During minor discharge peaks (water level in the river < 1.5 m above the normal river stage), a water level oscillation in the cave lakes situated 40 to 190 m away from river is induced by the river level oscillation, but the river water does not enter any of the lakes. The groundwater chemistry in the cave lakes differs from that of the river water. Low bicarbonate content and high delta C13 values indicate that some of cave lakes' waters have undergone CO2 degassing and calcite precipitation. During a major flood (recurrence interval > 100 years, level rising 7 m above the normal stage), the river water rapidly flooded the caves through openings in the river canyon (flood-flow injection), while those connected to the river via alluvium only were flooded by an elevated groundwater stage, and the resulting water level rise was only about 50 percent of the river level increase. A simple hydraulic model was successfully used to simulate and explain the water table oscillations in the cave lakes. Flood-flow injection has recently been substantially reduced by low-permeability, fine-grained late Holocene fluvial sediments that cap coarse gravels in the river floodplain. Fast speleogenesis by flood injection would be expected in periods when the river canyon was bare or filled by gravel alone (glacial periods, transition to Holocene). Ice jams causing local increases in the river level are recognized as one of factors that can be important in speleogenesis. Workplace Institute of Geology Contact Jana Popelková, popelkova@gli.cas.cz, Tel.: 226 800 273 Year of Publishing 2013
Number of the records: 1