There are important quantities of groundwater in the area of Ljubljansko polje which provide drinking water for the wider area of Ljubljana, so it is necessary to strive to protect and to recharge the aquifer. The knowledge of the water flow through the unsaturated zone and recharge of aquifer is crucial to ensure the adequate quantity and quality of the groundwater. A measuring device that collects leachate samples to determine its quality and quantity is called a lysimeter. It is also used to determine the water balance of soil profile. The water balance assessment provides an insight into how the groundwater is recharged and restored. With the help of build-in monolith weighing lysimeter in Kleče in Ljubljana I have assessed the water balance for the period from March 2014 to February 2015. For assessment of water balance I have used the mass measurements of lysimeter and outflow. The precipitation and evapotranspiration were determined from the changes in the mass of lysimeter. I have described and classified large precipitation events based on their duration, intensity and the amount of precipitation. I have estimated the duration of evapotranspiration and precipitation based on the change from the graph which represents the mass of the lysimeter. From the individual precipitation events I have deduced that the chosen period was considered extremely wet. In the selected hydrological year, precipitation contributed to storage of water within unsaturated zone (positive change of storage within the lysimeter), as well as to the recharge of the aquifer (positive outflow).
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