This paper shows a profile of hydrodynamic conditions present in a Skawa river portion, where fish populations have been found. The river portion surveyed is characterized by a changing gradient and varying morphology, and by a locally diversified velocity and intensity of flow turbulence. The longitudinal and transversal sections of the river bed were geodetically surveyed; the granulometric composition of the fluvial deposits was studied. Using an Acoustic Doppler Velocimeter (ADV), the river flow velocity was measured at three sites: above the riffle, in the riffle, and below it. The measurement results were used to compute shear stresses in the river bed, velocity distributions, and intensity distributions of turbulence. Based on the study, three types of habitats were identified. Using a method known as MEM (Mesohabitat Evaluation Model), the river flow within the zone of the site above and in the riffle was classified as a normal flow, whereas the flow below the riffle was classified as a fast river flow. The fact that the two habitats were classified as zones with normal flow proves that the assumed criterion, i.e. a wide range of shear stress values showing two orders of magnitude does not adequately incorporate changes in hydrodynamic conditions revealed through the survey conducted.

In the paper results of numerical modelling of water flow conditions in fishladers close to nature which are bypass channels designed as a natural stream and with habitat elements were presented. The simulations results were compared with laboratory measurements of vertical distributions of velocity at different habitats which occur in natural streams: from pool to fast run and riffle. There were measured three components of velocity v_x, v_y i v_z at characteristic points of longitudinal profile and cross-section: (1) at rapids, (2) inside and (3) outside turbulence zone for different bed configurations and size of bed material. The measured values were used to calculate velocity profiles, average velocities and characteristics of local flow conditions. This is an attempt to calculate a water flow parameters in nature base on laboratory measurements using similitude concept.

The work presents results of a research done on the usefulness of exploiting sediments accumulated in the Rożnów reservoir. Physical and chemical properties have been determined for samples taken from three pits and boreholes. The aim of the research was to investigate the possibility of using the sediments for plants growth, to measure the probable weight of one cubic metre of the material for transport, and also to determine the toxic elements content in the sediments.

City parks play the main role of leisure and recreation for citizens, but not without significance is their role in ecological structure. The priority in maintaining the parks is their cultural values, historical material and condition dendroflora. Ground cover is usually being neglected, but as shown in the study carried out in Lublin, regardless of the size and location, it has the most synantropic character and actions being undertaken do not improve the natural values and aesthetics. The ground cover of Lublin parks contains 174 species, but only in two of them (Saxon, Academic) the number exceeded 100 species. The dominant species are trampled gardens or transitory forms similar to meadow, synantropic and shrubs. Clearly there is a lack of any references of ground cover to the forest communities.

Lawns of urban areas are enriched over time by species occurring spontaneously. To determine the diversity of the lawns, phytosociological studies have been performed. They have shown significant differences. The lawns were distinguished into three groups: settlement lawns, street lawns and park lawns – each group having different species composition. Almost 224 species have been found in the ground cover, 53 in the settlement lawns, 190 in the street lawns and 105 in the parks. Despite the difficulties with the assigning the lawns to phytosociological units, nine synanthropic communities and trampled turf have been distinguished. Differentiation of lawn turf is dependent on the habitat, the area occupied and human interaction. On the other hand, large variation is beneficial ecologically and aesthetically.