The study investigates the physical, rheological and sedimentation parameters of two characteristic mud samples taken from the reservoir Sulejów in the area of the intake of drinking water for the town of Łódź. Rheological research was conducted using a rotational viscometer Rheotest 2, Couette-Searle type. The limit volumetric concentrations of the two muds were found to be 1.4 and 1.8%, respectively. Using the relationships established by Migniot, the volumetric concentrations corresponding with the transition from easy erosion to hard erosion were calculated. Sedimentation studies provided a basis for estimating the characteristic times of mud settlement. Finally, the average critical flow velocities, enabling the erosion of the top layer of mud to begin, were determined and were found to be 1.16 and 1.37 m · s-1, respectively. As the mean discharge of the water intake is 2 m3 · s-1, the water flow to the intake has the average velocity of 0.0154 m3 · s-1, which value is about 80 times smaller than the mean velocity causing mud erosion. Therefore, already after 2–3 days of settling, the cohesive mud deposited in the water intake area will not be eroded by the water stream flowing to the intake.

The research compared two variants of a digital elevation model (DEM) in the triangular irregular network (TIN) version, one constructed with breaklines and the other without such lines. The data for DEM were derived from contour maps with a scale of 1 : 5000. The two models were employed in slope studies for 1236 farmland parcels. It was found that the absence of breaklines has an influence on the results of slope studies. For the study area, the differences with the results of slope studies based on the breaklines--containing DEM constituted up to 10%. In addition, using the latter model produced a stricter conformity between the contours of the dominant slope classes, drawn in the slope studies, and the real borders of land parcels. The research proved the usefulness of incorporating breaklines in the TIN versions of DEMs intended for the purposes of farmland analyses.

The study investigates the influence of various ecosystems (agricultural vs. urban) surrounding a watercourse on the chosen indicators of water quality. In the years 1996–2001, water was sampled once a month from eleven cross-sections of the watercourse Kadaň and examined for the concentrations of dissolved oxygen, biodecomposable organic matter (BOD5), and organic substances (CODMn). The mean values of the respective indicators in the research period were: O2 – 7.26 mg ⋅ dm^-3, BOD5 – 2.12 mg ⋅ dm^-3, CODMn – 3.32 mg ⋅ dm^-3. On average, the O2 concentration was lowest in summer and autumn, most likely because of the intensive biological decomposition of organic matter, and had higher values downstream of agricultural areas than downstream of villages. BOD5 was lowest in the months of January to March, whose thermal conditions were unsuitable for the decomposition of organic matter by microorganisms living in the stream, and highest in May. The indicator reached higher values downstream of villages and tended to fall on the segments surrounded with agricultural areas, suggesting that the self-purification of water took place there. CODMn was lowest in December to March, and highest in June to August. This indicator had higher values downstream of urbanised areas, which may be due to the discharge of raw sewage into the watercourse. As follows from the results, various ecosystems differently influence the indicators of surface water quality.

The study determined the loads of selected chemical components deposited by precipitation and flowing away from the area of a partly built-up microcatchment with agriculture and animal farming dominating in its land-use pattern. The research was conducted in the hydrological years 2000 and 2001 within the microcatchment of the Wronowiec watercourse, 1.60 km2 in area, situated in the western part of the Małopolska province. Water for analyses was sampled twice a month and examined for the concentrations of total suspended solids, ammonium and nitrate nitrogen, phosphates, dissolved substances, sulphates, chlorides, calcium, magnesium, potassium, manganese and iron. Those values and the measured values of precipitation and outflow were used to compute the loads of the respective components. The results obtained corroborated the thesis that atmospheric precipitation constitutes an important source of non-point pollution. The loads of components carried away by outflow were larger than those delivered by rainfall, except manganese and phosphates for which the former were smaller than the latter. The results provided a further evidence to prove that rural settlement and animal farming with poor sanitation contribute substantially to the pollution of outflow waters.

The study determined the loads of selected chemical components deposited by precipitation and flowing away from the area of a small catchment used for agriculture and animal farming. The research was conducted in the hydrological years 2000 and 2001 in the Włosień stream catchment located in the western part of the Małopolska province. Water for analyses was sampled twice a month and examined for the concentrations of total suspended solids, ammonium and nitrate nitrogen, phosphates, dissolved substances, sulphates, chlorides, calcium, magnesium, potassium, manganese and iron. Those values and the measured values of precipitation and outflow were used to compute the loads of the respective components. The mean annual loads of N-NH4, PO43-, Mn2+ and Fe2+/3+ did not exceed 2 kg ⋅ ha-1, those of N-NO3 approximated 10 kg ⋅ ha^-1, those of Mg²⁺ and K⁺ were of ca 20 kg ⋅ ha^-1, and the loads of Cl- exceeded 50 kg ⋅ ha-1. The other components were removed in greater amounts: SO₄^2- and Ca²⁺ – over 100 kg ⋅ ha^-1, and total suspended solids – over 200 kg ⋅ ha^-1. The largest loads carried away by water were those of dissolved substances – 791 kg ⋅ ha^-1. The loads of components delivered by precipitation were smaller than the loads carried away by outflow, except for ammonium nitrate, phosphates and manganese. A comparison of the results of this research with the findings from other studies confirmed that the agricultural and animal-farming use of a catchment contributes to the pollution of surface waters: the component loads flowing out of the area of the Włosień catchment were larger than for the catchments not brought under pressure from the keeping of farm animals.

The study discusses the levels of nutrient contamination of river waters in the Barycz river catchment as dependent on the natural and economic conditions of the catchment. The research was based on the results of author’s studies on the concentration of nitrogen and phosphorus compounds in the river waters within the catchment in the period 2000–2002 and the data from the National Environmental Monitoring for the hydrological years 1993–2002. The natural and economic conditions of subcatchments were characterised by defining the land-use pattern, soil types, climatic conditions, and point sources of contamination lying in the catchment area. It was found that the contamination of river water is higher in catchments with dominant heavy soils and intensive agricultural production (Orla and Rów Polski) than in catchments with light soils and a high proportion of forests (Sąsiecznica and Barycz up to the Łąki gauging section).

The study attempts to establish the pattern of the climatic water balance for the Zielonka Forest as a typical example of forested areas in the Wielkopolska region based on a 20-year-long (1986–2005) hydrometeorological record. The period ended with a balance surplus of 229 mm and an annual average surplus of 11 mm. The meteorological conditions were quite favourable for water alimentation in winter half-years. Relatively high air temperatures, stimulating evapotranspiration, were then accompanied by high and stable precipitation. The general pattern of the climatic water balance was rather typical for Wielkopolska. As a rule, the balance was negative in summer half-years and vegetation seasons, and positive in winter half-years. Further studies are needed to explain the impact of the high frequency of warm periods and the wide variability of precipitation in summer half-years and vegetation seasons on the dynamics of evapotranspiration and the climatic water balance.

Research carried out in two hydrological years differing in the pattern of meteorological conditions aimed to investigate changes in the groundwater table level and the water reserves in a 1-metre layer of soil within a small river catchment with varied forest site types. It was found that irrespective of the forest site type the two parameters exhibited a similar cyclical pattern and their values depended mainly on the meteorological conditions, particularly on the amount and distribution of precipitation. It was confirmed that the low level of grounwater table in the vegetation season does not affect significantly the water reserves of the surface layer of soil.

The research was carried out in the hydrological years 2004 and 2005 within the catchment of a mid-forest pond situated in the southern part of the Wielkopolska Lowland. The results of measurements of the water levels in the pond and the groundwater levels in the surrounding forest sites were analysed against a background of the atmospheric conditions existing in this area in the study period. It was found that the water levels in the pond are significantly related to the groundwater levels in the forest sites adjacent to the reservoir. In winter half-years, groundwaters from the adjacent areas supplied the pond, whereas in summer half-years, the latter fed the groundwaters of the forest sites.

In the years 1999–2001 an attempt was made to reclaim a plot of land near Wrocław, lying fallow for a long time. The studies compared the effects of two variants of soil moisture and five variants of fertilisation on plant yields and the productivity of fertiliser compounds and water from sprinkling irrigation. The fresh matter yields of plants grown in rotation: turnip – spring barley – serradella were found to depend on the water--fertiliser variant and to vary in the ranges: turnip (roots) – 8.1–51.0 t · ha-1, spring barley (grain) – 1.11–2.95 t · ha-1, serradella (green matter) –3.12–12.44 t · ha-1. The results indicate that the best production effects were usually achieved under sprinkling irrigation (adjusted so as to cover water deficits) and fertilisation with farmyard manure or farmyard manure combined with NPK. Covering the water deficits in the vegetation season contributed to the satisfactory yielding of plants on the soil formerly lying fallow. Sprinkling irrigation had also a part in adjusting the amount and stability of yields of the plants in rotation, and made it possible to cultivate spring barley in atypical soil conditions.

The studies conducted in the Gnieźnieńskie Lakeland in the summer seasons of 2001 and 2002 provided the basis for determining the abundance and species richness and diversity of zooplankton in the littoral zone of two lakes heated by waters discharged from power stations, and for describing the relationships between water thermal conditions and the density and structure of taxocoenoses. The effect of water temperature on the zooplankton was estimated using the Spearman rank correlation. Over the whole study period, the zooplankton in both water bodies exhibited a high species richness and a wide species diversity (expressed as the Pielou index) but a relatively low abundance and biomass. No significant relation was found between water temperature and the total abundance, biomass and diversity indices of zooplankton. On the other hand, there were significant relations between water temperature and the abundance and biomass of individual taxonomic groups.

The research carried out on the Dymer river, a small watercourse in the eastern part of the Olsztyńskie Lakeland, aimed to determine the quantitative and qualitative changes in the phyto- and zooplankton caused by the operation of a small hydropower station. Taxonomic identification was done by using common methods and keys. The vegetation of the reservoir created by damming the river water was studied on the basis of phytosociological records, and the plankton was investigated on the basis of research made at three dates of the vegetation season at sites located upstream and downstream of the dam. In the water reservoir, numerous macrophyte associations of well-developed structure were found to occur. The reservoir itself is also attractive for plankton communities. Among algal groups, Bacillariophyceae account for the largest proportion of the whole algal plankton community. Due to their intensive development and distinct domination, the proportion of the other groups of algae is small. The species compositions and taxonomic structures of the phytoplankton living upstream and downstream of the dam are rather similar, differences concern only the forms in which some species occur. Namely, the colonies of Stephanodiscus downstream of the water turbine are disintegrated, and the coenobia of Pediastrum are deformed and fragmented. The damage is mechanical in nature and is done when water flows through the turbine. Upstream of the dam, in shallow, fertile and sunlit areas, large patches of Enteromorpha intestinalis f. maxima have developed. The zooplankton is dominated by Rotatoria. Among others, some rare, thermophilous species of Rotatoria, typical of warm, shallow, extremely fertile water bodies, occur in the water reservoir. The size of Protozoa community in the water environment downstream of the dam is higher than upstream of it.