The scour development in time during multiple floods and equilibrium stage and the assessment of flood damage risk for bridge abutments have been investigated. A method for computing scour development in time at hydraulic structures during multiple floods was used. The test confirmation of the method allows us to perform computer modelling of scour processes and estimate the influence of floods with different probability, duration, frequency, and sequence on the depth of scour. It was found that the scour parameters increase with decreasing probability and with increasing duration and frequency of the floods. The sequence of floods can increase or reduce the scour development in time, depending on their probability. The successive floods of the same probability considerably increase the value of scour depth. The results obtained are presented.