Long-term changes in the hydrological regime of high mountain Lake Morskie Oko (Tatra Mountains, Central Europe)

2018

E3S Web Conf.

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Abstract. The paper presents the analysis of the course of ice phenomena on four lakes (Lednica, Żnińskie Duże, Biskupińskie, Powidzkie) in central Poland in the period 1976-2015. The obtained results show changes in their ice regime that occurred over the last 40 years. An advance of the term of decline of ice cover was determined (by 2.5 day·dec -1 on average for all lakes), as well as a reduction of duration of ice cover (by 4.4 day·dec -1 on average for all lakes), and a decrease in its maximum thickness (by 2 cm·dec -1 on average for all lakes). Such a situation should be associated with the observed warming, as confirmed by the course of air temperature for station Gniezno, where in the period of the winter half-year (November-April), an increase in temperature was recorded by 0.37°C·dec -1 .

Section: Resultssupporting

confidence: 79%

Variability and course of occurrence of ice cover on selected lakes of the Gnieźnieńskie Lakeland (Central Poland) in the period 1976–2015

2018

E3S Web Conf.

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“…Diagram of the effect of damming lakes on groundwaters in lake catchments: 1-groundwater table, 2-drilled water table of confined aquifer, 3-stabilised water table of confined aquifer, 4-direction of flow of groundwaters, 5-direction of infiltration, +Hincrease in the water level in the lake, +Q s -increase in statistical resources in the catchment, +Mf-increase in filtration to deeper aquifers, >q 1 -decrease in unitary groundwater inflow to the lake, -q 2 -reversal of the direction of groundwater flow in deeper aquifers (source: Nowak in press) water balance. Many factors can cause a decrease in the water level in lakes, as described in detail by numerous analyses (Ptak et al 2013;Bonacci et al 2015;Choiński et al 2016;Wrzesiński and Ptak 2016;Ptak et al 2017;Skowron and Jaworski 2017;Volchak et al 2017). In the context of the observed climate changes, activities aimed at water retention in the catchment will be of increasing importance.…”

Section: Resultsmentioning

confidence: 99%

The effect of a water dam on Lake Powidzkie and its vicinity

Bulletin of Geography. Physical Geography Series

2018

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The paper presents an attempt to assess the effect of damming of lakes on water resources, based on the example of Lake Powidzkie (Central Poland) and its catchment. The region in which the analysed object is located has the greatest water deficits in Poland. The co-occurrence of unfavourable natural and anthropogenic factors contributed to a considerable reduction in the water resources retained in the lake. Particularly low water levels were recorded in the 1990s and in the first decade of the 21 st century. The situation was not improved by a water dam constructed on the outflow from the lake in the 1960s, due, among other things, to neglect in its exploitation. With regard to the modernisation of the dam in 2010 and the favourable hydrological situation in the winter of 2011, it was possible to retain the excess water and substantially reduce its outflow. The restoration of the lost water resources, and the hydrological benefits of this were still observable several years later. Problems related to water deficits are becoming increasingly common in many regions of the world. One solution to mitigate such a situation may be, among others, to dam natural lakes. This is simpler, cheaper, and less invasive for the environment than the construction of new water reservoirs.

“…It should be emphasised, however, that lakes as concave landforms with positive matter balance (overgrowing, filling with sediments) successively lose their retention capacity [15][16][17][18]. Changes in water resources accumulated in lakes overlap with climatic fluctuations, manifested in water level fluctuations [19,20], or direct human interference [21,1].…”

Section: Resultsmentioning

confidence: 99%

Potential use of lakes as a component of small retention in Wielkopolska

2018

E3S Web Conf.

Self Cite

Abstract. In the context of the observed climatic changes, unfavourable extreme situations occur increasingly frequently, manifested by, among others, the occurrence of droughts and floods. In the case of Poland, the central part of the country, in administrative terms covering the Wielkopolskie Province, is considered a region with a deficit of water resources. Such a situation was and is determined by a combination of natural and artificial factors. The former ones result from low precipitation and high air temperatures. The latter are the effect of intensive economic development, including large-scale meliorations. Measures mitigating this unfavourable phenomenon are related to the expansion of small retention. Its scale in Wielkopolska is the largest in the country -both in terms of the number of objects and volume of accumulated water. The key component of increasing retention is damming of lakes. According to the presented results, considerable reserves are still available in its scope. With the assumption of increasing water level in lakes by 0.2 m, it could cause an increase in water resources by 31 million m 3 , and assuming such an increase at a level of 0.5 m, by 78 million m 3 .