一、前言在水文计算和洪水预报中,流域面积为500—5000平方公里的中小河流产流汇流的计算是经常遇到的问题。近年来,由于电子计算机的应用日趋广泛,同时采用了“单元面积”作为产汇流的基本计算单位,经坡面和河糟汇流演算到总出口断面, I. Introduction In hydrological calculation and flood forecasting, the calculation of runoff of small and medium-sized rivers with a drainage area of ​​500-5000 square kilometers is a frequently encountered problem. In recent years, due to the increasingly wide range of applications of electronic computers, the “unit area” is adopted as the basic calculation unit of production and convergence. After calculating the total export section by the slope surface and the river confluence,