Flood-Frequency Analysis with Historical Data in China

Abstract

The U.S. Geological Survey has participated with the People’s Republic of China since 1981 in a scientific and technical exchange of hudrologic data and analytical techniques. The chinese have been documenting historical flood elevations at thousands of sites in China since about 1950. Information has been found at a few sites to establish flood elevations for extraordinary events occurring as much as 2,000 years ago. Peak discharges for many of the historical flood events have been quantified by using stage-discharge relations. hydraulic modesl. The Chinese have used the historical data extensively in their analyses of flood frequency for design purposes. Frequency curves are developed by a acombination of analytical and graphical methods, with the Pearson Type III distributin and Weibull plotting positions. The upper part of the curves are strongly influenced by the historical data.