In Poland there are several methods used for determination of the design flood hydrographs. Among the others, the method developed by Hydroprojekt is used. According to the authors' knowledge, this method has not been published yet. The method assumes that the design flood hydrographs are to be determined based on the real registered floods in a given gauged cross-section. The method uses the random number generator from the range of (-0.1, 0.2) independently for time instants of the hydrograph rising and falling limbs. This enables that the hydrographs have different time courses at different peak discharges. The study analyses the results received from this method in comparison to the Cracow method, assuming that the model hydrograph is the rainfall hydrograph, unimodal with the biggest registered discharge. The Cracow Method is chosen as the most objective one because of the calculation procedures which enable to determine the average time course based on 8 biggest flood hydrographs, and this method enables to determine the design flood hydrograph volume during its construction based on the linear correlation. The comparative analyses were conducted for the reduced volume, i.e., flood volume at the discharges bigger than the peak discharge with given exceedance probability, Q50%. The ...
Methods of hypothetical flood waves determining with the Cracow method developed for the Upper Vistula area are unlikely to be implemented by the common engineering practice in case when their verification was conducted only for one region. One of the methods is the Cracow method which is used for determining the flood waves in gauged catchments, whereas the other called the volume formula, is meant for ungauged catchments. In this method the wave volume is calculated by a formula, whereas its wave course is determined on the basis of a unit flood wave by means of SCS UHG method. An attempt was made in the paper to apply both methods for the catchment in the Odra river basin. The Nysa Kłodzka river was selected as a pilot catchment, in which 12 gauging stations were identified, for which the assessment of results was conducted using the criterion of hypothetical flood wave volume. Additionally these results were compared with the results obtained using the Hydroproject method. Conducted assessment allows to state that the Cracow method and the volume formula of hypothetical flood waves determining may be applied in the Odra basin. Verification of the methods and satisfactory results obtained in geographical region, ...
