Funding: Federal Emergency Management Agency.
Observed high water marks that document historic flood events can be valuable data to reduce the uncertainty associated with predicted flood elevations and inundation areas on the extensive portions of the nation's streams that do not have streamgages. These HWMs are an extremely valuable complement to the nation's streamgage data. One of the limitations associated with HWMs and historic flood inundation maps is that the frequency of the associated events is unknown. This project documented ways to establish flood frequencies associated with floods in which HWMs have been established.