We discuss a study that aimed to understand the genesis and inflow conditions of abstracted water by intake with induced infiltration located at a mountain river. A simple approach based on a combination of two research techniques was used: two-component water mixing modelling and studies of the variability of concentrations of environmental tracers in a dynamic test. This approach is versatile, easy to apply and modify, and can be good method for controlling surface/groundwater interactions. We used the gas tracers because gas exchange and dissolution of gases in infiltrating rainwater gives it a unique gas signature that is largely retained in groundwater. We focus on understanding river/aquifer interactions at the scale of reach of an intake. To understand these issues, a two-day field hydrogeological experiment based on a pumping test of increasing intensity was conducted. At each pumping stage, groundwater and river samples were collected to determine the concentration of noble gases, CFCs, SF6, stable isotope content, and chemical composition of the water. The study results indicate a short pressure propagation time between the intake and the river, which results in inflow of water already at low water abstract by the intake. Despite limited river water inflow, there was a continuous hydraulic contact river/aquifer, largely independent of changes in pumping intensity. As pumping intensity increased, the river/aquifer hydraulic system tended towards stabilised conditions of mixing and inflow to the intake. In general, a small proportion of river water (up to 26%) was found in the exchange flux between the river and groundwater.

Aim of the study: The aim of this study was to assess the impact of land development on the chemistry of groundwater. Material and methods: The scope of the study was to analyse the variation in chloride content and the magnitude of electrolytic conductivity over the years 2004-2017 for separate groups of wells in the city of Nowy Targ.Due to the significantly different usage of the land within which the groundwater intakes are located, a grouping of the groundwater intakes was introduced taking this factor into account. Physico-chemical analyses of the samples taken were carried out and archival data was already used.Non-parametric statistical tests such as the Kruskal-Wallis test and the median test were carried out to find statistically significant differences between chloride content and electrolytic conductivity magnitude between the selected groups of intakes. Results and conclusions: The results of the study showed that groundwater chemistry in the analysed wells depends on both natural factors and the nature of land use and the degree of urbanisation. The analyses concluded that land development has a dominant influence on water quality. The Orava-Nowy Targ Basin is a region where groundwater is characterised by a high susceptibility to contamination, and this susceptibility is due to hydrogeological conditions. The results of the tests showed statistically significant differences in chloride content and electrolytic conductivity values between the analysed groups of intakes. The lowest values of the analysed variables, were observed for intakes located in undeveloped areas, far from sources of anthropogenic pressure.