A Model Analysis of Observed and Predicted Climatic Changes in Groundwater Recharge in a Small River Basin

— The relationship between groundwater recharge in a small river basin to the current and expected climatic changes in the European area of Russia has been analyzed using the catchment basin of the Zhizdra River (Kaluga Region) as an example. The analysis is based on modeling of moisture transformation processes on the earth’s surface and moisture transfer in the unsaturated zone. The global climate predictions of five CMI5 Coupled Atmosphere–Ocean General Circulation Models (GCM) have been applied to forecast the groundwater recharge in the second half of the 21st century using the LARSWG5 forecast weather conditions generator. Despite the fact that all used GCMs predict a warming by 2–6°C in the studied region, the difference in the predicted recharge values is still considerable due to the difference in the predicted dryness index.