应用推理公式推求不同形状小流域设计流量

Application of Reasoning Formula to Calculation Design Discharge of Small Watershed with Different Basin Shapes

针对采用推理公式推求小流域设计洪水,当净雨历时小于汇流历时时引进流域矩形概化假定使计算获得的洪峰流量偏小,基于矩形、菱形、椭圆形流域形状应用推理公式推导了倒三角形、扇形流域的最大共时径流面积,并归纳了洪峰流量的统一表达式,减小了因流域最大宽度的随意取值导致的误差。实例结果表明,该方法为不同形状小流域设计流量提供了有效可行的计算方法。

As to deduce the design flood of small watershed with reasoning formula, choosing the rectangular section watershed of substitution form results in smaller peak flow if the net rainfall duration is smaller than the runoff concentration duration. The maximum synchronic runoff area of inverted triangle and fan shaped section watershed are obtained on the basis of rectangle, rhombic and oval section watershed. Then a unified expression formula of the peak flow is summed up, which reduced the error caused by choosing the value of watershed maximum width randomly. The results of instance show that the proposed method provides a feasible approach of calculation design flow for different shape section small watershed.