Long-term Groundwater Regime Trends in the Agricultural Areas

Abstract

Long-term data on hydrological regime change of the groundwater situated in moraine moraine sandy loam and peat soil in Lithuanian karst zone presented in the article. The aim of the paper is on the basis of long-term groundwater studies to determine the water level trends. Groundwater level fluctuations mainly dependent on the ground type. The nearest land surface groundwater level (61-174 cm) was measured in peat soil (well 1), in mineral soil (well 2) was deeper (309-584 cm). Correlation between data of the annual precipitation and groundwater level in mineral soils (r2=0.416, tact.= 3.48>t95%=1.74) was more significant than in peat soils (r2=0.185, tact.=1.96 >t95%=1.74). The widest fluctuations of groundwater level occurred in mineral soil (well 2). According to Mann-Kendall test the groundwater level significantly increased in February, April and December. In winter the thickness and duration of seasonal freezing decreases, frequent thaw increased feeding of the aquifer.