The research involved a detailed analysis of transformations in water relations in the Wieczno Południowe (Wieczno South) lake drainage basin in central Poland, in the physical geographical region of the Chełmno Lakeland. Significant changes were identified in the water relations in the catchment, which were caused by a number of anthropogenic factors. The most significant factors include land development works, changes in land use (a decrease in wetland area in favour of arable land), and the extraction of water from Lake Wieczno South (for irrigation purposes) and the creation of a weir construction on its outflow. It has been shown that in recent years the drainage basin’s water resources have been affected by climate fluctuations manifested as an increase in sums of evaporation. As a result of the deterioration of water relations in the catchment, the hydrological type of some lakes (Płużnica, Wieczno North and Wieczno South) have changed, which unexpectedly resulted in an improvement of their water quality. Taking into account the forecasts for further climate change, this factor will probably have a decisive influence on the water relations of the studied area in the coming years.
This paper presents an attempt to model water-level fluctuations in a lake based on artificial neural networks. The subject of research was the water level in Lake Drwęckie over the period 1980-2012. For modelling purposes, meteorological data from the weather station in Olsztyn were used. As a result of the research conducted, the model M_Meteo_Lag_3 was identified as the most accurate. This artificial neural network model has seven input neurons, four neurons in the hidden layer and one neuron in the output layer. As explanatory variables meteorological parameters (minimal, maximal and mean temperature, and humidity) and values of dependent variables from three earlier months were implemented. The paper claims that artificial neural networks performed well in terms of modelling the analysed phenomenon. In most cases (55%) the modelled value differed from the real value by an average of 7.25 cm. Only in two cases did a meaningful error occur, of 33 and 38 cm.
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
The aim of this paper was to present the possibility of integrating LIDAR data with bathymetric measurements in order to assess the changes in water resources and morphometric parameters. The area of study was Lake Kiedrowickie (Poland). A change in most of the morphometric parameters has been observed. Especially important was the drop in water resources which amounted to more than 30%. A significant decrease (13.4%) was also observed in case of the lake surface. In conclusion we state that the integration of valid bathymetric measurements with the LIDAR data gives the full capability to model the changes of lake morphometric parameters with unprecedented accuracy. A significant complementarity and synergy of applying both techniques has been stressed.
The paper presents the changes that have occurred in the morphometry of Lakes Gopło and Ostrowskie, which are located
in central Poland. The analysis covered the period characterised by increased human interference into the water cycle, which has
been taking place continually since the mid-eighteenth century. On the basis of available cartographic materials (aerial photographs,
topographic maps, bathymetric charts of the lakes) and the authors’ own field measurements digital terrain models were developed
for the immediate environment of the surveyed lakes. These models, in turn, were used for measuring basic parameters characterising
the external dimensions of the lakes (surface area, length and maximum width, shoreline length) and their underwater relief (volume,
maximum and average depth). In addition, the selected indicators of the shape and form of the lake basins were determined. The results
showed a drastic reduction of water resources of the two lakes. The basin of Lake Gopło covers only the deepest parts of the former
reservoir, accounting for only 23.3% of the lake before 1772, and 32.5% of its former volume. In the case of Lake Ostrowskie the surface
area and volume decreased, respectively, by 23.5% (74.9 ha) and 21.3% (6 695 000 m3). Such large changes in surface area and volume of
both lakes have contributed to significant changes in other morphometric parameters and indicators. In particular, significant changes
were observed in relation to such morphometric characteristics as length and maximum width, as well as average and maximum depth.