Central Europe experienced catastrophic rainfalls and flooding in 2010. This paper discusses a decommissioned shaft that was flooded by surface water, which led to displacement of shaft backfill and an inrush of large amounts of water into an underground pumping station. The weather conditions for the period preceding the inrush, the hydrogeological conditions, the quantity of water that entered the mine dewatering systems, and the underground hydraulic connections are all described. Uncontrolled inflow of water as a cause of backfill saturation and the hazard for active underground infrastructure were analysed. A need to rebuild damaged infrastructure was identified. The case study highlights the need to improve underground mine closure requirements to ensure safe conditions above ground, particularly in densely populated areas.

The layout of the dewatering system in open-cast mining must be adapted to mining assumptions and to the size of expected inflows, which, in turn, depend on natural conditions and the operation of other mines and groundwater intakes, affecting the arrangement of the hydrodynamic field. This case study analyses possible dewatering solutions related to a change in the mining drainage system: decommissioning by flooding of a depleted deposit and dewatering of a new one located in the vicinity. As part of numerical modelling, a solution was sought to minimise the environmental impact of drainage. Forecast calculations for two drainage alternatives were made. One of the solutions follows the classic approach: independent dewatering of the new excavation. The second solution assumes the recirculation of waters from dewatering of the new mine through their discharge into a closed and flooded pit located in the vicinity. The results of the forecasts for both variants point to the modification of the hydrodynamic field resulting from expected volumes of inflows and different environmental effects. The use of numerical simulations assisted the selection of the optimal dewatering solution.

Precipitation elasticity provides a basic estimate of the sensitivity of long-term streamflow to changes in long-term precipitation, and it is especially useful as the first assessment of climate change impact in land and water resource projects. This study estimated and compared the precipitation elasticity (εp) of streamflow in 86 catchments within Pakistan over 50 major rivers using three widely used analytical models: bivariate nonparametric (NP) estimator, multivariate NP analysis, and multivariate double logarithm (DL) model. All the three models gave similar values of elasticity in the range of 0.1–3.5 for over 70–75% of the catchments. This signifies that a 1% change in the annual mean precipitation compared to the long-term historic mean annual precipitation will amplify the streamflow by 0.1–3.5%. In addition, the results suggested that elasticity estimation of streamflow sensitivity using the multivariate DL model is more reliable and realistic. Precipitation elasticity of streamflow is observed high at altitudes ranging between 250 m and 1000 m while the longitudinal and latitudinal pattern of εp shows higher values in the range of 70–75 and 32–36 decimal degrees, respectively. The εp values were found to have a direct relationship with the mean annual precipitation and an inverse relationship with the catchment areas. Likewise, high εp values were noticed in areas where the mean annual temperature ranges between 15 and 24 °C.

The carbonate fissure-karstic aquifer of Upper Jurassic age is the main aquifer in the Cracow Upper Jurassic Region (CUJR). The aquifer is recharged directly or indirectly by Quaternary or Quaternary-Cretaceous overburden of varying permeability, which predominates diffused recharge. Concentrated recharge occurs locally and has a diverse nature. Field studies carried out in 20 quarries show moderate permeability of the unsaturated zone of carbonate massif. Karst funnels are filled with rubble and clay material and dominate filled fissures with an opening b \ 10 mm. The average surface fissure porosity of massive with chalky limestones and bedded limestones reach 0.12 and 0.45 %, respectively, while fissure permeability coefficient is, respectively, k S 6.60 9 10 -5 and 1.27 9 10 -3 m/s. The average karstification in quarries was determined as n k = 2.5 %. Tracer studies, carried out in an unconfined carbonate Zakrzówek horst in Cracow (Kraków), document vertical migration of infiltrating water through the systems with different hydraulic resistance, with a flow rate from 8.1 9 10 -6 to 4.9 9 10 -5 m/s and the lateral migration velocity between communicated caves from 6.94 9 10 -6 to 1.06 9 10 -4 m/s. The significant presence of poorly permeable overburden and moderate fissuring and karstification of rock in the unsaturated zone of CUJR are reflected in the assessment of the Upper Jurassic aquifer vulnerability to contamination, performed by a modified DRASTIC method. In the area of unconfined karst, occupying 55 % of the area, vulnerability to contamination is high, while as much as 45 % of the area is characterized by medium and low vulnerability.

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