Revision to Flood Hazard Assessment at the Savannah River Site

Requirements for the Natural Phenomena Hazard (NPH) mitigation for new and existing Department of Energy (DOE) facilities are outlined in DOE Order 420.1. This research examines the hazards posed by potential flooding and represents an update to prior reports issued by the Savannah River Site (SRS) in 1999 and 2000. The facility-specific probabilistic flood hazard curve is defined as the water elevation for each annual probability of precipitation occurrence (or inversely, the return period in years). New design hyetographs for both 6-hr and 24-hr precipitation distributions were created using statistical techniques and meteorological data (precipitation) collected at the SRS subsequent to the prior reporting period. These hyetographs were used in conjunction with hydrological models of various basins within the SRS. For numerous locations of operational interest, peak flow discharge and flood water elevation were determined. In all cases, the probability of flooding of these facilities for a 100,000 year precipitation event is negligible.