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<br />,1 <br />I <br />^i <br />J, <br />I <br />i <br /> <br />FLOOD FLOW <br />WATERSHEDS: <br /> <br />FREQUENCY FOR UNGAGED <br />A LITERATURE EVALUATION.!.! <br /> <br />by Richard H. McCuenll, Walter J. Rawls2/, <br />Gary T. Fishe~/, and Robert L. Powel121 <br /> <br />ABSTRACT <br /> <br />This report contains the results of an evaluation of recent publications <br />on flood flow frequency estimation at ungaged locations. The objective of the <br />literature evaluation was both to identify alternative procedures currently <br />used for flood-frequency estimation at ungaged locations and to gather infor- <br />mation regarding the accuracy, reproducibility, and practicality of the <br />alternatives. The evaluation was limited to those studies involving watersheds <br />that have not undergone man-made changes, such as urbanization or channeliza- <br />tion. The procedures were separated into eight categories: (1) statistical <br />estimation of Qp' (2) statistical estimation of moments, (3) index flood <br />estimation, (4) estimation by transfer of Qp' (5) "empirical" equations, <br />(6) single storm event:rain frequency is proportional to runoff frequency, <br />(7) multiple discrete events, and (8) continuous record. Four important con- <br />clusions of this literature evaluation are: (1) there is a noticeable lack of <br />consistency in the structure and presentation of results of hydrologic studies; <br />(2) the literature does not accurately reflect what is currently being used in <br />hydrologic planning and design; (3) the literature does not provide the infor- <br />mation, such as cost and computer requirements, that is necessary for potential <br />users to select a procedure from, among the many that are in the literature; and <br /> <br />11 Contributed by the Hydrograph Laboratory, Agricultural Research Service, <br />Beltsville, Maryland, in cooperation with the Departments of Agricultural and <br />Civil Engineering, University of Maryland, College Park, Maryland. <br /> <br />1/ Associate Professor, Department of Civil Engineering, University of Mary- <br />land, College Park, Maryland. <br /> <br />11 Hydrologist, Hydrograph Laboratory, Agricultural Research Service, U.S. <br />Department of Agriculture, Beltsville, Maryland. <br /> <br />~ Faculty Research Assistant, Department of Agricultural Engineering, Univer- <br />sity of Maryland, College Park, Maryland. <br /> <br />1/ Graduate Research Assistant, Department of Civil Engineering, University of <br />Maryland, College Park, Maryland (presently with Greenhorne & O'Mara, Inc., <br />Riverdale, Maryland). <br /> <br />1 <br />