Larger than Maryland: Site-Specific PMP & PMF for a 14,000-Square Mile River Basin

ABSTRACT ONLY - When the Federal Energy Regulatory Commission (FERC) asked the owner of eleven hydropower dams in the Southeast US to review their 30-year-old design flood analysis, the power company decided to undertake a state-of-the-practice analysis to update the Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF) for each dam. In partnership with Applied Weather Associates, the nation’s leading extreme meteorology consultants, the FNI team has analyzed site-specific PMP and developed hydrologic and hydraulic models representing the total 14,000 square mile river basin.
Applied Weather Associates’ PMP analysis included updating the storm record with numerous recent extreme storm events, providing gridded PMP depths with storm specific temporal and spatial patterns, and providing gridded rainfall analysis for hydrologic model calibration and validation. This input provided high quality, accurate meteorological data that allowed FNI to represent the complex hydrology of the basin more accurately and to concentrate their analysis on the hydrology and engineering unique to the basin. (continued)