Katarzyna Kubiak-Wójcicka, Sławomir Brózda and Agnieszka Sznajder
The paper presents hydrographic changes in a river system and their influence on the legal classification of watercourses in Poland. As a case study, the watercourse Motwica, right tributary of the river San has been analysed. The main objective of this paper is an attempt to analyse whether the Motwica should be classified as flowing or standing water and the legal grounds for such classification in the Water Law Act. On the base of archival and contemporary cartographic materials’ analysis it has been determined that the Motwica should not be classified as natural watercourse because its significant part flows in an artificial channel.
The work attempts to determine the impact of hydrotechnical structures on regimes of rivers. The aim of the article is to compare hydrological regimes of the rivers Gwda and Drawa due to the differences of hydrotechnical works located on both rivers. The Gwda River is heavily managed by hydrotechnical infrastructure. Presently, there are twelve hydropower plants located along the entire length of the river. The Drawa River, on the other hand, has little hydrotechnical infrastructure. Only two hydropower plants are located on the Drawa River. The study of the hydrological regime was carried out on the basis of the analysis of changes of water stages and ice phenomena. River profiles selected for the analysis were located downstream of hydrotechnical works, i.e. hydropower plants. The conclusions were based on the comparative analysis. The impacts were identified as the differences in processes described by the analyzed parameters
This paper presents lake surface area changes that have taken place in the Gwda River basin. The studies were conducted on the basis of the cartographic materials released since the beginning of the twentieth century until the present times. The starting point was the area of all lakes greater than 1 ha which are present on the MPHP map from 2010. The assessment of the changes in the surface area of lakes in the Gwda River basin during approximately the last 100 years was possible thanks to the use of German topographic maps, so called Messtischblatt, at a scale of 1: 25 000 released between 1919 and 1944. The area of all the studied lakes has decreased by 465.09 ha (from 12783.62 ha at the beginning of the twentieth century to 12318.53 ha at the present time). Despite the general trend of lake atrophy, in particular cases one may observe an increase in the water surface area. This is the result of hydrotechnical works leading to river and lake damming, which in turn hampers the pace of atrophy.
The paper presents impact of meteorological drought on hydrological drought on the Vistula River in Toruń in the period of 1971-2015. It uses index method for the assessment of hydrological drought threat degree as a result of multi-month lasting meteorological drought. Based on the values of the SPI-24 (24-month standardized precipitation index) it was determined that meteorological drought in Toruń appeared six times and the total time of the phenomenon was 33% of the studied interval. Periods of hydrological drought on the Vistula River in Toruń have been determined based on the values of the SWI-24 (24-month standardized water level index). It has been found out that hydrological drought appeared four times and its total time was 10% longer that the meteorological drought. Based on the values of both indices (SPI-24 and SWI-24) correlation coefficient for months, seasons and years, it was found that the relation between both kind of droughts is weak (r < 0.5). That result is also confirmed in the distribution of both kinds of drought. Only in 32 months (8% of the total time) the intensity of the two simultaneously occurring drought was at least moderate. The achieved results revealed that the hydrological drought was occurring periodically, independent on meteorological drought. Hydrological drought was also influenced by the external factors (hydropower plant in Włocławek, Major Groundwater Basin - GZWP) and climate factors appearing in the upper and middle part of the river basin.
This article discusses the problem of property and use of waters and the legal aspects of the definitions of lakes in particular. To achieve this, the authors reviewed the acts on Water Law from 1922 up to the present day. They proved consistency in the application of the water law. From the hydrological point of view the lake belongs to stagnant waters. The definition included in the Water Law act is contrary to this depiction of the lake. The act reads that the lake may be classified as stagnant or flowing water depending upon the existence of the natural, permanent or seasonal, inflow (or outflow) of the lake. This obviously constitutes a discrepancy between the scientific and legal definition of the lake.