The results of estimation of the probable annual flood flows with the use of two 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. 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 AM and POT data indicate for nonsignificant differences in probable flood flows. ...