Acta Scientiarum Polonorum

Abstract: The main goal of this article was comparison of estimated Instantaneous Unit Hydrograph – IUH calculated with four methods: on the basis of recorded data, SCS formula, with Rao, Delleur and Sarma equations and hydrological analogy with the use of IUH transformation from the adjoining stream gauge. The object of case study was Służew Creek catchment, located in Warsaw (Poland). The IUH based on the Nash model was used to transform effective rainfall into direct runoff, moreover the comparison of four methods was based on Nash model characteristics: tp – time to peak of IUH, and up – peak of IUH, estimated for each method. The measured IUH has been chosen as a reference standard of IUH for the others methods. Conducted analysis has shown that IUH estimated with the use of Rao, Delleur and Sarma equation has been the closest one to measured IUH. Therefore, in situation of limited information, this method could be useful to calculate and predict flood flows in urban catchments with relation to designing hydro-engineering objects.