Geologists record very low groundwater levels2015-08-14
The Lithuanian Geological Survey under the Ministry of the Environment has informed that this summer in some parts of the country the levels of groundwater are very low. The groundwater level measurement data shows that the groundwater level, which started decreasing in April and May, may stay low until September or even October.
The Lithuanian Geological Survey monitors changes in groundwater levels. The level of groundwater is measured once daily by automatic level sensors in 20 sites throughout Lithuania. The data obtained is immediately transmitted via a telemetric system.
In July, the groundwater level in most parts of the country dropped below normal. The greatest difference (30–40 cm) was recorded in Kybartai, Rykantai and Buivydžiai (Vilnius District). The groundwater level in these locations has already reached the low level zone. A better situation is observed in the western (Vėžaičiai), northern (Biržai), and central (Raseiniai, Dotnuva) regions of the country where the water level was higher than, or close to the pluriannual mean for July. A groundwater level higher than normal was recorded in Ukmergė and Varėna where groundwater accumulates in sandy sediments and stays fairly deeply (7–10 meters from the ground surface).
Average water staying level (in metres) in July 2015.
Compared to the summer of 2014, this year the groundwater level in most parts of the country is considerably lower. Last year, only the situation in western Lithuania (Vėžaičiai, Laukuva) was worse.
The pluriannual level curves allow us to forecast that groundwater level decrease will continue in September and October. If the amount of precipitation in this time period is smaller than normal, the groundwater level in individual districts may reach the lowest level of the past decade.
The actual groundwater level in a specific location depends not only on meteorological but also on geological conditions. Groundwater that does not stay deep (up to 5 metres) and that is present in clayish sediment reacts to changes in meteorological conditions most readily – the level of this groundwater raises and falls by several metres per year. The level of groundwater staying deeper (> 7 m) changes by several centimetres, and such changes only become evident several months later.
Groundwater feeds surface water bodies, and its staying depth affects the condition of aboveground ecosystems. The natural flora has adapted to the dominating groundwater levels and their fluctuations, but extremely low or high groundwater levels can be detrimental for it.
Public Information Unit
14 August 2015