There is an urgent need to improve flood-frequency estimation methods for floodplain management, dam safety, human impact, climate change, and numerous related environmental disciplines (NRC, 1988, 1999; Swain and Jarrett, 2000; Jones et al., 2001; Levish, 2001). Worldwide, floods are the most destructive events related to meteorological processes. Probabilitistic hazard-estimation requires extrapolation well beyond our limited gage data for floods with annual exceedance probabilities in the range of 10^-2 to 10^-4. Poor understanding of flood frequency contributes to unnecessary loss of life and increased flood damages, and conversely, can lead to costly overdesign of infrastructure located on floodplains, and questionable flood-frequency estimates for other situations (Jarrett and Tomlinson, 2000). Effective design of flood risk management plans and environmental science projects require an improved estimate of flood risk (NRC, 1999). The need to develop more accurate, efficient, and robust flood-frequency estimates requires an improved understanding of the physical processes involved and augmenting the observational record by incorporating historical flood and paleoflood data.

This paper provides an overview of recent paleoflood research, including the integration of historical flood and paleoflood data into flood-frequency analyses for several water-resources applications. In addition, insights gained from paleoflood studies on human impact, climate change, and non-stationary hydrology will be presented.