The aim of this research was an assessment of impact of relocated Mała Wełna river channel on water conditions in the adjacent areas. In this paper also a fasibility to increase river flow capacity with the purpose of maintaining river channel dynamic equilibrium was presented. Field observations and measurements were carried out in hydrological years of 2000–2008 in Mała Wełna river catchment down to Kiszkowo crosssection. The main cause of valley flooding on the reach from Zakrzewo to Kiszkowo were hydraulic conditions at the relocated Mała Wełna river channel. The river cross-section geometry and its channel slope caused that at the high-water discharge SWQ the channel capacity of the river is too low. A lack of the river banks and bottom maintenance has had strong negative impact on the river capacity. To improve the river flow capacity and the drain ditches “A” and “B” it is necessary to make modernization of hydraulic structures and the whole water system in the catchment of the Mała Wełna river. Before this it is necessary to make a detail geodetic measurement of these areas. ...
The article attempts to establish regional dependencies for calculation of the Snyder's model parameters. This model belongs to a group of synthetic unit hydrographs, whose parameters are determined based on the characteristics of catchments. This creates the possibility to use this model in uncontrolled catchments to calculate maximum probable flows and to construct hypothetical waves. In practice, this model is used worldwide. It is recommended for practical use in Poland, however due to the lack of established values of model parameters specific to Polish conditions, its use is rather unreliable. The optimization of the model parameters was carried out for the selected episodes of rainfall-runoff in the cat-chments of Rudawa, Kamienica, Grabinka, Stobnica, Jasiołka and Wielopolka. Hydrological data used in the calculations were provided by the Institute of Mete-orology and Water Management National Research Institute in Warsaw and were derived from the Annals of hydrology for the Vistula basin. The analysis revealed that the Snyder's model very well or well describes the observed flooding incidents (values of the effectiveness ratio E ranged from 68 to 93%). The parameter values of the Snyder's model, which depend on the shape of the catchments, levelled slope of the watercourse and the CN parameter, ...
The study involves a preliminary analysis of short-duration high-intensity rainfall events in the area of Cracow. The events were selected from a 2-year data record from the MPWiK (Miejskie Przedsiębiorstwo Wodociągów i Kanalizacji [Municipal Water and Sewage Company]) in Cracow. A spatial analysis was carried out by comparing rainfall events with highest single totals which occurred at the same time at all observed precipitation stations. Extracted were nine cases from the data record of 2013 and ten from the data record of 2014. Each of the analysed events was classified according to the Chomicz scale for rainfall intensity in order to distinguish maximum rainfalls, in particular of the following types: heavy rainfalls, rainstorms and torrential rains. Additionally, observed were cases of the most unfavourable rainfall events, i.e. ones with the highest totals in the observed year. In both 2013 and 2014, certain areas in Cracow were observed to be characterised by a pattern of repeating rainfall types. Also, a change in the rainfall category was observed from lower into higher and reverse in certain areas represented by the same gauging stations. At the stations located in varying distances within one urban area of Cracow, the intensity of rainfall varied from ...
