Rapid development of karst landscape in North Lithuania – monitoring of denudation rate, site investigations and implications for management

Karst processes are intensively developing in North Lithuania and are related to Upper Devonian gypsum layers that occur under the Quaternary cover. During the last two decades of the 20th century and the first years of 21st century more intense karst processes are witnessed. The intensity of the karst processes are indicated by new sinkholes that severely damage crops, constructions and communication systems. The monitoring of gypsum karst processes comprises measurement of rate of chemical denudation of gypsum and intensity of formation of sinkholes. The chemical denudation is being measured since 1964 in this region. Since 1978 the intensity of karst denudation increased by 30% and it probably was a main reason for more frequent formation of sinkholes. This phenomenon is correlated with climate change – increasing air temperature and decreasing duration of seasonal frozen ground, which respectively impacted hydrological and hydrogeological regimes. In order to prevent damage by karst processes on constructions the following means are under implementation: detailed engineering geological mapping of urban areas (for town-development planning), engineering geological investigations of construction sites, engineering assessment of damaged buildings.