Preliminary long-term predictive modelling of groundwater resources in view of climate change – a case study from eastern Poland

The paper discusses an effective and simple approach to preliminary long-term predictive modelling to the estimation of the effects of predicted climate change on groundwater resources in aquifer recharged by rain infiltration for the end of the 21st century. The groundwater resources in an analysed catchment were assessed based on predicted precipitation and air temperature from seven climate change projections in two sets of the Intergovernmental Panel on Climate Change (IPCC) greenhouse gas emission scenarios (SRES), associated with various regional climate models (RCM). The predicted groundwater resources were obtained by diminishing the predicted renewable resources by recent environmental flows in a river dewatering the catchment. The predicted reserve was assessed taking into account the forecasted groundwater abstraction. The study revealed that the predicted groundwater reserve depended on the assumed prediction model, based on particular SRES and RCM ensembles. The groundwater resources in the study area at the close of the 21st century are expected to considerably decrease when compared to the reference period 1971–1990. The future groundwater reserve assessed by the climate change model based on IPCC emission scenario B2 connected with the regional climate model HIRHAM and regional climate model RCAO, may decrease when compared to the reference period, by 51 or 92%, respectively. In view of the IPCC emission scenario A2 assumptions, this preliminary predictive modelling shows that there may be a shortage of groundwater resources in the analysed catchment in the final decades of the 21st century.