The paper presents the analysis of hydrological drought of the Biebrza river to the Burzyn gauge and Narewka river to Narewka gauge in multiyear 1951–2002. Hydrological drought is usually expressions of deficiencies is surface water supplies. This phenomena is the last stage the drought process and is identify with low flows in river bed. The examined catchment area is part of the Podlaska Lowland where droughts occurred most often in Poland. The research described in this paper was concentrated on the Biebrza valley, which is a unique wetlands area in Central Europe and on the Narewka valley within the Bialowieza Forest, the latter being a natural heritage in the global scale. The Biebrza Wetlands and Bialowieza Forest hydrogenic sites conditions depends on ground and surface water levels and thus, a hydrological droughts is a danger to them. The methodology used in this paper describes the hydrological drought as the situation, where river discharges are below some arbitrarily chosen threshold level. The size of the threshold discharge was established in dependence on aim of study. Truncation level value of drought was applied as statistical value Q90% determined from flow duration curve with the upper discharges. This paper include the proposition the ...
Nowadays, in literature there are a lot of indices and factors designed to assess drought periods and water needs. Indices are presented in different spatial and temporal scale, from regional to global and chiefly are dedicated to agriculture and economy for making decision. Their application mainly depends on target and data availability. Such application imposes methodological approach; it means that obtained results should be comparable for different regions. Therefore drought indices are express as single number related to selected region. Some of them, especially the ones that are simple to calculate, are based only on one feature - precipitation for instance as a difference between total precipitation from investigated period and established norm from multiyear data. Others indices are based on more features as temperature, snow-cover, surface water and groundwater supply etc. Although it is hard to select a prori which index is the most effective, for each region the one that matches the best local environment and climatic conditions should be appointed. The paper presents a survey of indices for drought assessment and the results obtained for selected indices in Nysa Klodzka basin. ...
Streamflow drought is a period of continuing low flows in river. Depending on the time of year streamflow drought are caused by long-term shortage of preci-pitation or long-lasting temperatures below zero. Streamflow droughts are one of the current problems in the management of water, especially in the light seen in recent years, frequent occurrence of droughts. The goal of this work consists in analysis of long-term changes in selected characteristics of streamflow droughts (duration, deficit) in the Zagożdżonka river at the Płachty Stare gauging station. The Zagożdżonka catchment is situated in the strip of the Central Polish Lowlands, in the region where droughts are the most frequent. The Zagożdżonka small river catchment is one of a few in Poland with long-term records on rainfall and runoff. To identify droughts in daily discharge hydrograms, truncation levels SNQ and Q90% were used. The study did not show a tendency to pre-existing low flow periods in the catchment Zagożdżonka. Analysis of the statistical significance of trends in the course of aggregation of the individual years of deficits of droughts and duration of droughts in the Zagożdżonka river at the Płachty Stare showed a positive trend on the level of significance 0,1. In ...
Poland is considered to have scarce water resources and to be one of the few countries in Europe which are in danger of a water deficit. Surface water resources in the Lubelskie Province are significantly lower than the country's average and are among the lowest in Poland. This calls for sustainable and sparing water-resources management, combined witch particularly intensive protection of their quality and quantity. The most successful and effective way of forming water resources is surface-water retention aimed at mitigating the water deficit, especially in periods of drought. Catering for the continuously-growing food demand is a primary objective for agriculture in Poland and in the Lubelskie Province (good types of soil). The drainage infrastructure and hydro-engineering buildings are the key factors in increasing the efficiency of production. It allows the sustainable use of water circulation in an environment shaped by man for agricultural purposes. The article includes the condition, selected examples of, and the requirements for, the hydro-engineering buildings to be used in drainage systems for sustainable water management in agriculture.
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This paper addresses the problem of how drought definition by POT and SPA methods influences drought characteristics. Using the 1984-2013 daily flows at 24 selected gauging stations in the Dunajec river basin and assuming two threshold levels Q70% and Q95% and four minimum drought durations (5, 7, 10 and 14 days) as the pre-set criteria, it was shown that, when compared to the POT method, the application of the SPA method usually leads to less number of droughts and, consequently, of longer duration. The SPA method, differently from POT, reduces dramatically the number of inter-event times, which suggests that some adjacent POT droughts may be dependent and should be pooled. ...
