We studied the structure and development of the Holocene floodplain of the Labe (Elbe) River by radiocarbon dating sections of the upper and middle courses of the river. We focused on geomorphological and sedimentological conditions, mineralogy and the chemical composition of sediments. We established the stratigraphy of the Holocene deposits of the floodplain. The results of our investigation of fluvial sediments imply that several abrupt changes in temperature and precipitation occurred during the Holocene. These changes led to intervals of hydrological disequilibrium, which caused the formation of two Holocene terraces and a contemporaneous floodplain. The lower terrace was flooded and covered with sediments upon which the recent floodplain formed. During the Holocene, there were four periods during which large tree trunks were deposited in the fluvial sediments, indicating periods of extensive flooding. The supposition that these events were of more global scale is supported by the results of investigations made on the Holocene floodplains of other regions.

During hydraulic dumping of ashes at a sludge bed of the power plant at MElnik (north of Prague), new springs originated which wetted houses and properties at the small village of Podvlci. The sludge bed as well as the village lie at the southwestern margin of the alluvial plain of the Labe (Elbe) River at the foot of a slope built of Cretaceous sedimentary rocks. By analyzing the concentrations of radiocarbon and tritium, it was possible to determine the origin of the water and the ratio of the modern and original groundwater in the new springs in the surroundings of the sludge bed. To substitute the present dump the operation of which should be stopped, establishing of a new one has been proposed within the alluvial plain. By means of stable isotopes and radionuclides, the relations between the groundwater in the Quaternary sediments and in the underlying Middle Turonian confined aquifer were studied, because changes in the hydrogeological regime have to be expected due to the operation of the proposed new sludge bed.