黄土区无水文资料小流域设计洪水计算方法

Calculation Method of Design Flood in Small Watershed without Hydrological Data in Loess Area

兰州地区大部分季节性沟道没有相应水文资料,无法获取准确的洪峰流量,给沟道治理和管理带来很多不便。因此,建立适用于黄土区无水文资料小流域设计洪峰流量计算方法对流域防灾减灾工作具有重要意义。以甘肃兰州地区无水文资料山洪沟道为研究对象,结合甘肃省科学院地质自然灾害防治研究所调查评价数据,通过Kendall协同系数检验和灰色关联分析,分别对沟道流域特征参数的一致性和特征参数与设计洪水计算相关性进行检验分析,选取沟道面积与主沟道长两个特征参数建立适用于兰州市山洪沟道设计洪峰流量计算经验公式。结合兰州市洪水经验公式法和“铁一院”法对比分析,3种计算方法两两对比均值误差分别为:新经验公式法-兰州洪水经验公式相对误差均值约14.4%、新经验公式法-“铁一院”法相对误差均值约17.8%、兰州洪水经验公式法-“铁一院”法相对误差均值约20.3%,新经验公式计算结果介于兰州洪水经验公式与“铁一院”法之间,具有一定准确性及合理性,能够更加高效、便捷地进行设计洪峰流量推求。同时新经验公式推求设计洪峰流量仅涉及两个特征参数且可准确量化。

Most of the seasonal channels in Lanzhou area do not have corresponding hydrological data,and it is impossible to obtain accurate flood peak flow,which brings a lot of inconvenience to channel management and management.Therefore,it is of great significance to establish a design flood peak flow calculation method for small watersheds without hydrological data in the loess area for disaster prevention and mitigation.Taking the mountain torrent channel without hydrological data in Lanzhou area of Gansu Province as the research object,combined with the survey and evaluation data of the Institute of Geological Natural Disaster Prevention and Control of Gansu Academy of Sciences,the consistency of the characteristic parameters of the channel basin and the correlation between the characteristic parameters and the design flood calculation were tested and analyzed by Kendall synergy coefficient test and grey correlation analysis.Two characteristic parameters of channel area and main channel length were selected to establish an empirical formula for calculating the design flood peak flow of mountain torrent channel in Lanzhou City.Combined with the comparative analysis of Lanzhou flood empirical formula method and ‘Tie Yi Yuan' method,the mean errors of the three calculation methods are as follows:the average relative error of the new empirical formula method-Lanzhou flood empirical formula is about 14.4%,the average relative error of the new empirical formula method-‘Tie Yi Yuan' method is about 17.8%,and the average relative error of the Lanzhou flood empirical formula method-‘Tie Yi Yuan' method is about 20.3%.The calculation results of the new empirical formula are between the Lanzhou flood empirical formula and the ‘Tie Yi Yuan' method.It has certain accuracy and rationality,and can be more efficient and convenient to calculate the design flood peak flow.At the same time,the new empirical formula deduces that the design flood peak flow only involves two characteristic parameters and can be accurately quantified.