The paper describes research aimed at expanding scientific knowledge of radioactive isotope²²²Rn occurrence in groundwaters flowing in crystalline rocks, including its spatial and temporal changes. The research, conducted in an area characterized by medium radon potential, was intended to determine the values of²²²Rn activity concentration in groundwater in this type of areas. The²²²Rn activity concentration in groundwaters discharged from investigated springs oscillated between 35.3 and 272.0 Bq/L. The authors discovered possible prevalence of radon groundwaters in areas with medium radon potential, which is the reason why all groundwaters intended for human consumption or household use in such areas should be subject to obligatory monitoring of²²²Rn activity concentration. In the event of identifying occurrence of waters with²²²Rn activity concentration of at least 100 Bq/L, their purification by removing radon is necessary before they are supplied to a water distribution network. At the same time, the research area can be regarded as an area with potentially medicinal radon water occurrence. Therefore, in areas with medium radon potential, groundwaters which are not suitable as a source of drinking water due to very high²²²Rn activity concentration in them can be used as medicinal radon waters in therapeutic treatments.

Areas of Western and Central Europe were severely affected by devastating droughts in 2003 and 2015. A sharp decrease in annual atmospheric precipitation led to diminished spring discharges. Analysis of the fluctuations in discharge from three groups of springs in the south of Poland, namely in the Sudetes and Carpathian mountains, and in the German province of Bavaria revealed an average discharge reduction ranging from 52 to 4%. The study proved the existence of a relationship between diminished groundwater recharge from precipitation and the type of rock forming the reservoir as well as the parameters of the rock in the drained catchment. Spring discharge regime was compared for various periods to show that a decline in the regime correlates with a decline in river flow rate; considering the continually changing weather patterns, this correlation is arguably a key factor in sustainable water management.

This study describes various groundwater flow systems in mountainous areas where both crystalline and hard sedimentary rock formations can be found. The research was conducted in the Sudeten Mountains, in the Kamienczyk catchment area, which covers 7.85 km² (south-western Poland). The water circulation system and the role of tectonic zones were identified and described following an analysis of the water inflow in river systems and sources, as well as measurements of groundwater tables in wells. The modulus of spring runoff equalled 3.81 L·s^-1/km², while the modulus of underground runoff amounted to 6.24-7.17 L·s^-1/km². The total discharge index equalled 15.80 L·s-1/km². Considering the results of the study, it can be concluded that for both the basins Kamienczyk and Kamionka groundwater runoff constituted 60-70% of all precipitation registered in the areas under study. The remaining 30-40% either evaporates or constitutes part of indirect and regional discharge. Areas drained by river sources are usually quite small, that is 0.1-0.5 km². In the nine years of periodic observations, the average temperature of spring water was in the range of 7.2-7.7 °C and the variations were very low. The study results demonstrate that the depth of circulation of the water taking part in spring water discharge is between 35 to 55 m below ground level. The temperature of water in wells in Cretaceous sedimentary rocks, which ranges from 7.8 to 11 °C, is suggestive, given the mixing pattern of water inflow from the depths of 150-200 m.

An attempt to explain the disappearance and decline in discharge rate of selected karst springs of the Opole region.

This paper presents the construction of a numerical three-dimensional model of the area of the Żelazny Most Mining Waste Storage Facility (MWSF). In the study area, the difficult geological conditions associated with glaciotectonics are accompanied by a complex hydrotechnical system of sediment deposition and sedimentary water drainage. In order to effectively reflect the water flow paths, a detailed schematization was carried out, using 700,000 boreholes and more than 300 hydrogeological cross-sections. In addition, numerous drainage sections, streams, and ditches were included to reliably assess the amount of saline water entering the underlying aquifers. This research was supported by magnetic resonance sounding (MRS) studies of the reservoir’s sediments. The MWSF is currently being expanded, so the work primarily focuses on illustrating changes in the hydrodynamic field resulting from the inclusion of the new southern section. Models of similar facilities have been implemented before, but in the current one, the combination of meticulous analysis of the hydro-structural system, the water balance, a significant amount of data, the size of the facility, and the use of an unstructured discretization grid in the calculations is undoubtedly innovative and will be an important contribution to the development of analogous solutions around the world.

Celem badań jest testowanie metody i wstępna ocena wielkości infiltracji efektywnej na podstawie wyników pomiarów temperatury w piezometrach w otoczeniu studni i stawów infiltracyjnych na terenach wodonośnych Wrocławia. Badania zmienności temperatury wód podziemnych w sieci obserwacyjnej na obszarze sztucznej infiltracji przeprowadzono w sieci 11 piezometrów. Wody pierwszego poziomu wodonośnego występują w aluwialnych osadach piaszczystych i zalegają na głębokościach 2–12 m. Roczne pomiary temperatur wód podziemnych w sieci obserwacyjnej na stałej głębokości (3–4 m) wykazały szeroki zakres zmian od 1,5 do 25,9°C. Przedstawiono charakterystyczne i typowe zakresy średnich zmian temperatur w przedziale 9,3–15,6°C zarejestrowane w 2018 r. Na podstawie profilowania termicznego w wybranym punkcie obliczono średnią wartość zasilania, stosując metodykę zaproponowana przez Taniguchiego (1993, 1994). Obliczona wstępnie wartość sztucznego zasilania wynosi 20,19 mm/d i odpowiada wielkości zasobów obliczonych na podstawie modelowania numerycznego.