VÝVOJ PODZEMNÍHO ODTOKU VE VÝCHODNÍ POLOVINĚ ČR

Abstract

The depletion of groundwater storage caused by the climate changes is frequently discussed issue. Thus, the baseflow evolution from 2006 to 2015 (at two locations from 1994 to 2016) was assessed at 10 watersheds situated in the eastern part of Czech Republic. Six observed watersheds are situated in the crystalline rocks (Strážek Moldanubicum and Orlice-Sněžník Unit) and four in sedimentary rocks (Vienna Basin, Ždánice Unit, Vysoké Mýto Syncline and Ústí Syncline). The evolution of the groundwater storage and baseflow is based on the springs and rivers flow rates evaluation respectively. The groundwater storage evolution from the spring watersheds was determined by the Maillet equation. The automated baseflow separation accomplished by PART (USGS) program was applied for the river watersheds and then expressed by linear regression in MS Excel. The long-term decrease of groundwater storage and baseflow was revealed in all observed watersheds. The rate of this decline is very different in each watershed and ranges from 10 to 85%. The increase of groundwater exploitation or change of vegetation cover or seasonal distribution of groundwater recharge was not confirmed. Relating to the correlation between precipitation and baseflow evolution, the reason for groundwater depletion resides in the decreasing amount of precipitation.