The degradation of river channels may occur downstream of hydraulic structures or may be a consequence of the uncontrolled exploitation of bed material or of the bed levelling. Such a process is especially visible in mountain streams because local degradation causes also local aggradation, which considerably affects the water-flow capacity of their channels. One of the factors that may be used for evaluating the equilibrium conditions of a river channel is the grain-size composition of bedload material. The grain-size composition changes both in the longitudinal profile and the cross-sections of the channel over the whole length of the degraded sector. The present paper addresses this problem using the Targaniczanka stream (Małopolska Province, Poland) as an example. The grain-size composition of the bed material was investigated along a 480 m channel sector and its variability was determined. The samples of bedload were collected by different ways: 9 samples were obtained by conventional method from the surface and/or subsurface layer, and 3 samples were obtained by freezing method using liquid nitrogen. It was found that the sorting of the bed material along the stream differs from that in the cross-sections, which is important for bedload transport or sediment deposition in those sections. The calculations were performed using the Meyer-Peter and Mueller modified formulas.

The geomechanical and hydrological degradation due to the underground mining of hard coal causes deformations to lands used for nature-related purposes (agriculture, forestry, etc.) and a high variability of soil properties. The present study analysed the spatial variability of soil texture in the layer 0–25 cm in a chosen post-mining area by use of the kriging method. The empirical semivariograms obtained for sand and clay fractions were smoothed with a spherical model. The analyses performed made it possible to draw maps showing fraction content isolines, displaying the spatial variability of soil texture, which can provide a basis for delineating the areas most prone to the hydrological degradation of soils.

Six composites with four levels of bulk density and porosity, formed of river sand, silt-clayey soil and peat substrate, were examined for water permeability. The tests were aimed to determine their usefulness for constructing the carrying layer of football fields. The water permeability (permeability coefficients) and selected physical properties of the composites were investigated using standard methods. The average values of permeability coefficients at the largest proportion of sand in the composites ranged from 1.4 to 17.2 mm ∙ min^-1, and at the medium and smallest share of sand, it was of 1.5–8.8 to 2.9–13.9 mm ∙ min^-1, respectively, depending on bulk density and organic matter content. Considering water permeability, the composites met the requirements of the DIN 18 035 standard for natural deposits used for constructing a football field’s carrying layer.

The results presented in this paper are based on the observation of rainfall in the summer period, carried out in the area of the Agro- and Hydrometeorological Observatory Wrocław-Swojec of the Wroclaw University of Environmental and Life Sciences. The research data came from the years 1966–2007. Daily, nightly and 24-hour rainfall totals were investigated for 5-day periods, 10-day periods and months, and the number of events with rainfall during the day, night and 24 hours was analysed in ranges from 0.0–1.0 to 14.1–15.0 mm at 1 mm intervals. The trends of changes in rainfall totals in the 42-year period were assessed for the time steps used, and the percentage structure of rainfall was examined in individual months and depth ranges. In addition, the trends in the periods of occurrence of extreme rainfalls during the day, night and 24 hours were estimated. The analyses made it possible to determine to what extent the variation in the periods of rainfall occurrence can be an indicator of climate change on a scale of the point.

A forecast about the frequency of occurrence in southeastern Poland of the pluvio-thermal conditions that are unfavourable for principal cultivated plants was prepared for three scenarios of temperature increase (by 1.0, 1.5 or 2.0 ºC) over the long-term period average of 1901–2000. The simulation was carried out using Selianinov’s hydro-thermal coefficient whose values were calculated for each month in the growing season (April– –October) assuming steady precipitation and appropriately increased air temperatures. The critical values of Selianinov’s coefficient were established on the basis of how the state of cultivated plants in the field responded to the changing pluvio-thermal conditions. For the scenario with 2.0 ºC temperature rise, it can be expected that the frequency of deficient humidity conditions would increase from 23 to 33%, and that of excessive humidity conditions would decrease from 23 to 14%.