W artykule omówiono problemy związane z mała retencja, jakie mogą występować na obszarach użytkowanych rolniczo na przykładzie województwa lubelskiego. Pojawiające się coraz częściej deficyty wody zmuszają do racjonalnego sposobu zwiększania zasobów dyspozycyjnych wód przez ich magazynowanie w zbiornikach. Retencja to nie tylko magazynowanie wody, przeznaczonej do różnorakich celów, ale również regulacja kontroli obiegu wody w środowisku. Zapewnia to lepsze możliwości zarówno ochrony, jak i odnowy zasobów wodnych, a także racjonalnego gospodarowania nimi bez naruszenia równowagi środowiska przyrodniczego.
EN
In the article problems with small retention, which can occurs in agricultural areas as the example of Lublin province were discussed. Water deficits, which appear more frequently oblige to increase water disposal resources in rational way by its storing in reservoirs. Retention is not only water storage uses for divers purposes, but also regulation of water cycle control in environment. It assures better possibilities both protection and renovation of water resources, but also its rational management without violation of environmental.
The main objective of the paper is to estimate the influence of time of concentration (TC) on maximum flow in an urbanized watershed. The calculations of maximum flow have been carried out using the Rational method, Technical Release 55 (TR55) procedure based on NRCS (National Resources Conservation Services) guidelines, and NRCS-UH rainfall-runoff model. Similarly, three methods were used to calculate the overland flow component of the TC: the Kerby method, the Morgali and Linsley method and the NRCS travel time method. The TC was calculated in a watershed located in Krakow city in Poland, małopolskie voivodeship. Total area of the watershed has about 180 ha. It’s a highly urbanized watershed with a significant land cover (29.6% of total area) influencing the runoff, in the form of an impervious industrial area. The highest value of time of concentration was achieved for Morgali and Lindley method in case of the subwatershed with dominant pervious areas, as opposed to the NRCS method for the subwatershed with dominant impervious areas. The highest value of TC was obtained for NRCS method. With reference to the whole watershed, the highest values of the time of concentration were obtained for the MorgaliandLindley method and the lowest for the Kerby formula. Based on this study, authors recomended the Kerby method for estimating TC for overland surface dominated areas because this method requires only a small number of input parameters, that are straightforward to estimate.