关键词: 洪峰流量; 设计洪水; 量纲分析; 无资料地区; 小流域; 澜沧江; 怒江;

Abstract: It is difficult to deduce design flood for ungauged watersheds.The formula of flood peak discharge is of great significance to small watershed management and hydropower engineering design.However,the existing rational formulas do not work for small watersheds in Lancang River and Nujiang River in western China.Thus,the relationship between flood peak discharge and basin parameters was derived by dimensional analysis.The formula indices were determined using storm flood data of the hydrological stations in the Lancang River and Nujiang River Basins according to inference analysis.Then,the final flood peak discharge formulas that were available for ungauged regions were obtained.Besides,we purposed a formula to estimate upstream flood peak discharge based on the downstream flood peak discharge.Also,we simplified the final flood peak discharge formulas for small watersheds.The flood peak discharge formulas showed that flood peak discharge was proportionate to 3/4 power of the watershed area,1/2 power of the river slope,and 1/10 power of the storm intensity.Comparison of calculated results with the measured data showed that the formula had high accuracy,which could be used to estimate the design flood for small watersheds without or lacking data.

Key words: peak discharge; design flood; dimensional analysis; ungauged area; small watershed; Lancang River; Nujiang River;