In order to solve the problems of designing flood for the current reclamation of data scarce small to medium scale river basins, the method of estimating flood from rainfall data observed in river basins was proposed. Two approaches of US Rational Formula and “Zhongtie Method” were investigated in a case study of Zishui River basin for its adaptability. The estimation equations were established by adjacent river basins with similar catchment scales and observed hydrological data. Results indicated that design floods obtained by Zhongtie method are much more accurate than those by US Rational Formula. Therefore, Zhongtie method is a suitable approach for the design flood estimation in the small to medium scale catchments in China.
