Tom 14 (2014): Zeszyt 4 (December 2014)

The paper considers whether in recent years there have been changes in the structure of the water circulation in Lake Wigry, the main water body of the Wigry National Park. The volume and trends in the streams of water exchange in the lake have been assessed. They show that in recent years the horizontal water exchange is being reduced as the inflow to the lake is growing, mainly due to its main tributary, the Czarna Hańcza, while the outflow from the lake is decreasing. The paper examines whether these changes are reflected in the structure of the lake water circulation, which has been assessed on the basis of the lake water balance

The aim of the study was to locate and describe groundwater outflows in a selected lake basin. The study hypothesis was based on the fact that, according to the specialist literature, one of the forms of lake water supply is through groundwater outflows. It was also assumed that the lakes of the Kashubian Lake District are characterised by such a form of lake water supply. The time scope of the work included the period from January 2011 to September 2012. The spatial scope of the work included the area of Lake Raduńskie Górne, located in the Kashubian Lake District in north Poland. The research plot was in the north-eastern part of the lake. Office works were aimed at gathering and studying source materials and maps. Cartographic materials were analysed with the use of the MapInfo Professional 9.5. The purpose of the field work was to find the groundwater outflows in the basin of Lake Raduńskie Górne. During the field research diving was carried out in the lake. During the dive audiovisual documentation was conducted using a Nikon D90 camera with Ikelite underwater housing for Nikon D90 and an Ikelite DS 161 movie substrobe, as well as a GoPro HD HERO 2 Outdoor camera. During the project, four groundwater outflows were found. In order to examine these springs audiovisual and photographic documentation was made. To systematise the typology of the discovered springs, new nomenclature was suggested, namely under-lake springs with subtypes: an under-lake slope spring and under-lake offshore spring

The paper presents an analysis of the trophic status of two small retention reservoirs located in the Subcarpathian region: Blizne reservoir on the River Ladzierz and Cierpisz reservoir on the River Tuszymka. The capacity of the reservoirs is respectively 137,000 m³ and 22,000 m³ and they occupy an area of 11.46 and 2.3 hectares. The study was conducted from May to October in 2013 and in 2014. Samples of surface water were collected from two locations for each reservoir. Assessment of the trophic status of the reservoirs was based on the concentrations of phosphorus, nitrogen and chlorophyll a. Criteria available in the literature were used to assess the trophic status. The progress of eutrophication was also evaluated on the basis of the Trophic State Index (TSI). Analysis of the results showed that in the studied period the water of Blizne was on the border of eutrophic and hypertrophic. The fertility of the water of Cierpisz in the analysed period deteriorated from the eutrophic state to the border with hypertrophic

The article discusses water level fluctuations in lakes and the associated changes in the lake surface and water resources in the years 1992-2011. On the basis of detailed field studies carried out in the hydrological year 2011, short-term and dynamic changes in the lakes’ hydrology were determined. Changes in hydrological lake types were evoked by unexpected hydro-meteorological situations, in particular high precipitation totals and sudden thaws in winter. The main symptom of the lake type change was the restoration, after nearly 10 years, of channels connecting the lakes. In addition, a strong interdependence was recorded in the difference between evaporation and precipitation, as well as the mean annual ranges of lake water levels in the years 1992-2010

One of the soil fertility parameters is water content in the root zone; therefore the estimation of the transformation of water resources in mineral soils of Belarus is rather relevant. The analysis of plant available moisture content (PAMC) was conducted for the topsoil layer of 50 cm thickness for the period of monitoring from 1960 until 2001. Results were submitted as maps on the basis of which the spatial and time variability of the PAMC was estimated. The quantitative estimation of changes in the plant available moisture content was carried out with the help of gradients of linear trends