Probable annual floods in a small lowland river estimated with the use of various sets of data

The results of estimation of the probable annual flood flows with the use of various sets of data from a small agricultural lowland river are presented. The traditional statistical series are formed from the annual maximum (AM) flows of hydrological years. After examination of the homogeneity of the series, two sets of data were formed (AM1 of 34 elements and AM2 of 40 elements), which differed in the significance level of one of the stationary tests. The other series for flood frequency analysis has been formed by selecting peaks over threshold discharges (POT). A computer program, developed by IMGW (Institute of Hydrology and Water Management), and spreadsheet were applied for frequency analysis with the use of AM series and POT series, respectively. Results of computations with the use of AM1 and AM2 data indicate for nonsignificant differences in probable flood flows, and significant with the probable flood flow estimated with the POT data.