Flood frequency analysis based on simulated peak discharges
Flood frequency analysis based on simulated peak discharges
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DOI：
10.1007/s11069-013-0925-2
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发表时间：
2014-03
期刊：
影响因子：
3.7
通讯作者：
B. Saghafian;S. Golian;A. Ghasemi
中科院分区：
文献类型：
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作者：
B. Saghafian;S. Golian;A. Ghasemi
洪水频率方法从直接应用于观测的年最大洪水序列的统计方法，到采用将设计雨量转化为洪水流量的降雨-径流模拟模型。对统计洪水频率分析的依赖取决于几个因素，如选择的概率分布函数、函数参数的估计、可能的异常值和观测洪水序列的长度。通过采用本文的模拟方法，利用校准的水文模型将不同发生概率的流域平均降雨量转换为相应的峰值流量。采用蒙特卡罗方法考虑了降雨空间分布和前期土壤湿度条件的不确定性。对于任意给定的降雨深度，降雨空间分布的实现和AMC条件作为输入输入到模型中。通过将降雨转化为径流，模拟了不同重现期的洪水。该方法被应用于伊朗东北部的坦格拉分水岭。结果表明，降雨空间分布和AMC对不同重现期的洪峰流量有不同的影响。将模拟方法的结果与统计频率分析的结果进行了比较，发现在给定的重现期内，基于观测序列的洪水分位数大于相应的模拟流量。还值得注意的是，异常值的存在和统计分布函数的选择在增加两种方法结果之间的差异方面起着重要作用。
Flood frequency approaches vary from statistical methods, directly applied on the observed annual maximum flood series, to adopting rainfall–runoff simulation models that transform design rainfalls to flood discharges. Reliance on statistical flood frequency analysis depends on several factors such as the selected probability distribution function, estimation of the function parameters, possible outliers, and length of the observed flood series. Through adopting the simulation approach in this paper, watershed-average rainfalls of various occurrence probabilities were transformed into the corresponding peak discharges using a calibrated hydrological model. A Monte Carlo scheme was employed to consider the uncertainties involved in rainfall spatial patterns and antecedent soil moisture condition (AMC). For any given rainfall depth, realizations of rainfall spatial distribution and AMC conditions were entered as inputs to the model. Then, floods of different return periods were simulated by transforming rainfall to runoff. The approach was applied to Tangrah watershed in northeastern Iran. It was deduced that the spatial rainfall distribution and the AMCs exerted a varying influence on the peak discharge of different return periods. Comparing the results of the simulation approach with those of the statistical frequency analysis revealed that, for a given return period, flood quantiles based on the observed series were greater than the corresponding simulated discharges. It is also worthy to note that existence of outliers and the selection of the statistical distribution function has a major effect in increasing the differences between the results of the two approaches.