Changes in the groundwater levels and regimes in the taiga zone of Western Siberia as a result of global warming

Groundwater accounts for 30% of the world drinking water resources and is rarely taken into account in climate assessments. Climate change affects groundwater levels and regimes, but there is very little specific research on the future impacts of climate change on groundwater. This study examines data from 15 groundwater wells of various ages for the period from 1965 to 2015. To obtain reliable data, an analysis was made of the groundwater level changes in the upper hydrodynamic zone, which is not disturbed by anthropogenic activity. A statistically significant increase in the average annual groundwater levels in the study area was observed, in agreement with data indicating an increase in groundwater runoff in the winter season for large and medium rivers in the region. To explain the revealed changes in the groundwater levels, an analysis of the characteristic climatic changes (air temperature and amount of precipitation) and the groundwater runoff was performed. In winter, the unfrozen moisture content in the soil has increased; accordingly, groundwater recharge and groundwater levels have increased. Meanwhile, in summer, an increase in evaporation from the drainage basin has occurred as a result of the increasing air temperature. To some extent, this compensates for the changes in the annual runoff and groundwater levels that are hydraulically connected to the rivers.