[1] Merz and Blöschl (2008a, 2008b) proposed the concept of flood frequency hydrology, which highlights the importance of combining local flood data with additional types of information: temporal information on historic floods, spatial information on floods in neighboring catchments, and causal information on the flood processes. Although most of the previous studies combined flood data with only one extra type of information, all three types are used here in a Bayesian analysis. To illustrate ways to combine the additional information and to assess its value, flood frequency analyses before and after the extraordinary 2002 flood event are compared for the 622 km² Kamp river in northern Austria. Although this outlier significantly affects the flood frequency estimates if only local flood data are used (60% difference for the 100 year flood), the effect is much reduced if all additional information is used (only 3% difference). The Bayesian analysis also shows that the estimated uncertainty is significantly reduced when more information is used (for the 100 year return period, the 90% credible intervals range reduces from 140% to 31% of the corresponding flood peak estimate). Further analyses show that the sensitivity of the flood estimates to the assumptions made on one piece of information is small when all pieces of information are considered together. While expanding information beyond the systematic flood record is sometimes considered of little value in engineering hydrology because subjective assumptions are involved, the results of this study suggest that the extra information (temporal, spatial, and causal) may outweigh the uncertainty caused by these assumptions.