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AUTHORITY The USDI (United States Depa:-t~~-le::t c: t:lt: 1:-1,en:;r) 5a181\' o~ Da:Tl~, Progia:T. au::~or;zes the USSR (Bureau of Reclamation) to coordlna1e and rlanage the Depanment's Dam Safely Pcogram. Program activities include preparing Departmental poliCY and gUidelines, and assisting other USDI agencies in developing their dam safety programs, In this context, a need for the USBR to perform this study was identified, It is intended to help other USDI agencies develop hydrologic dam safety policy standards and practices, which are to be implemented Departmentwide, Specific authority for the Flood Section of the USBR's Engineering and Research Center to ,nitiate this study was provided in a memorandum from the Division of Dam Safety to the Division of Planning Technical Services, on July 7, 1983, as part of the SEED (Safety Evaluation of Existing Dams) Program. PURPOSE The purpose of this report is to provide data from "observed" flood events at various sites for comparison with the PMF (probable maximum flood) hydrograph for the same site, This comparison may be used to support the magnitude of the rainflood PMF hydrograph peaks produced as part of the SEED Program for the USBR and other Department of the Interior dams, This study covers the conterminous 48 States and is limited to historic rain-induced flood events. INTRODUCTION The eminent hydrologist R, D, Horton once stated that "flood magnitudes always continue to increase as the recurrence interval increases, but they increase toward a definite limit and not toward infinity" [1]' Nevertheless, for many hydraulic engineers, designers, and dam owners responsible for solving potential dam safety problems related to new hydrologic studies, the upper limit for new flood peaks may seem to be unbounded. For the USBR and all other Federal agencies involved with dam safety, the practical upper limit for flood design is the PMF, Starting in the mid-1970's, USBR flood hydrologists have produced hundreds of PMF studies for sites throughout the United States as part of the SEED Program, In most cases, the peaks of these PMF's have been several times the maximum recorded peak at the site studied This fact often generates an apparent lack of credibility in the hydrologist's work and has led to several Investigations of the methodologies used. This study shows that floods nearly as large as the PMF have recently occurred at various locations in this country, The procedures and data used to define the PMF's in this study are identical to . Numbers in brackets refer to entries In the bibliography.