河道水面线推求方法比较

Comparison of Methods for Calculating River Water-Surface Profile

水面线的推求是山洪灾害评价的关键工作,因此有必要探讨水面线推求方法。水面线推求方法主要采用水力学方法以及曼宁公式,对比两种方法的精度。选取有实测水位资料的孔家坡河道,该河段无区间汇水,应用两种方法分别推求河道水位,与实测水位资料进行对比,两种方法计算精度相接近。沿河村落分布广而多、河道比降较小的条件下,采用曼宁公式与水力学方法推求水面线精度相接近,可以采用曼宁公式简化计算方法。河道比降较大的情况下,曼宁公式计算精度较差,应采用水面线方法进行推求。

The calculation of water surface profile is the key work of the mountain flood disaster evaluation.Therefore,it is necessary to discuss the calculation method of water surface profile. The hydraulic method and Manning formula were mainly used to calculate the water surface profile,and the accuracy of the two methods was compared. The Kongjiapo river channel with measured water level data was selected. There was no interval water in the section. The two methods were used to calculate the water level of the river channel,and the calculation accuracy of the two methods was close to that of the measured water level data. Under the condition that there are many villages along the river and the river gradient is small,Manning formula could be used to simplify the calculation method because the accuracy of water surface profile is close to that of hydraulic method. In case of large river gradient,Manning’s formula has poor calculation accuracy,so the water surface profile method should be used for calculation.